Deck 48: Initiating and Adjusting Invasive Ventilatory Support

Question 1

Which the following are hazards associated with mechanical ventilation?
1) Reduced cardiac output
2) Liver failure
3) Increased work of breathing
4) Acute lung injury

A)1 and 3 only
B)1, 2, and 3 only
C)3 and 4 only
D)1, 3, and 4 only

Answer 1

D

Question 2

Which of the following clinical findings is least likely to be seen in a patient with acute hypoxic respiratory failure?

A) Confusion
B) Tachycardia
C) Hypotension
D) Dyspnea

Answer 2

C
Explanation: Clinical manifestations of acute hypoxemia and acute ventilatory failure are listed in Table 48-6.

Question 3

To stabilize a patient during the initial application of ventilatory support, which of the following parameters must be set?
1) Airway temperature
2) Ventilatory support mode
3) O₂ concentration (FiO₂)
4) Minute ventilation (f, V_T)

A)1 and 3 only
B)1, 2, and 3 only
C)2, 3, and 4 only
D)1, 2, 3, and 4

Answer 3

B

Question 4

In which of the following clinical conditions would noninvasive ventilation (NIV) be recommended?
1) Management of acute exacerbation of chronic obstructive pulmonary disease (COPD)
2) Management of premature extubation
3) Management of cardiogenic pulmonary edema
4) Management of acute respiratory distress syndrome (ARDS)

A)1 and 3 only
B)1, 2, and 3 only
C)3 and 4 only
D)2, 3, and 4 only

Question 5

Which of the following modes of ventilatory support would you recommend for a patient who can breathe spontaneously and only requires assistance to overcome the work of breathing created by the ET tube?

A) Pressure-targeted continuous mandatory ventilation
B) Pressure-supported ventilation
C) Volume-targeted CMV
D) Pressure-targeted intermittent mandatory ventilation

Question 6

Compared with a volume-cycled strategy, what are some potential advantages of pressure-targeted ventilatory support?
1) Limit and control of peak airway pressures
2) Direct control over inspiratory time
3) Provision of a decelerating flow pattern

A)1 and 2 only
B)2 and 3 only
C)1 and 3 only
D)1, 2, and 3

Question 7

What percentage of mechanical ventilated patients has a tracheostomy tube place at some point?

A) 5% to 10%
B) 10% to 15%
C) 20% to 25%
D) 30% to 35%

Question 8

Which of the following is the least frequent cause of acute respiratory failure needing mechanical ventilation?

A) Sepsis
B) Postoperative respiratory failure
C) Heart failure
D) Aspiration

Question 9

Which of the following is an advantage of Pressure Control Ventilation?

A) Higher mean airway pressure can decrease venous return.
B) VT varies depending on lung compliance, resistance, and patient effort.
C) Improved gas distribution allows for lower VT.
D) If VT or minute ventilation alarms are not set properly, alveolar hypoventilation and acidosis may not be detected.

Question 10

What goal(s) does the practitioner hope to achieve when selecting initial ventilatory support settings?
1) Optimize oxygenation.
2) Optimize ventilation.
3) Maintain acid-base balance.
4) Avoid harmful side effects.

A)1 only
B)2 and 3 only
C)1, 3, and 4 only
D)1, 2, 3, and 4

Question 11

Compared to a pressure-controlled strategy, what is the primary advantage of volume-controlled ventilatory support?

A) Provides a decelerating flow pattern.
B) Limits and controls peak airway pressures.
C) Improves patient-ventilator synchrony.
D) Guarantees a minimum minute ventilation.

Question 12

Which of the following is one of the modes of ventilation that may be considered when partial ventilatory support is indicated?

A) Assist-control pressure ventilation
B) Proportional assist ventilation (PAV)
C) Volume-control continuous mandatory ventilation
D) Assist-control volume ventilation

Question 13

Which of the following findings would you expect to see in a patient who has acute ventilatory failure with severe hypercapnia?

A) Jugular vein distension
B) Pale, dry skin
C) Bradycardia
D) Hyperresponsiveness and dilated pupils

Question 14

Which of the following represents a clinical situation where partial ventilatory support is commonly used?

A) Patient with head trauma
B) During weaning from continuous mandatory ventilation
C) While ventilating an asthmatic
D) In a drug overdose case

Question 15

Which of the following situations is most likely to call for ventilator settings of low volume and high rate while allowing for permissive hypercapnia?

A) Patient with ARDS
B) Patient with neuromuscular disease
C) Patient with chronic obstructive pulmonary disease
D) Child with croup

Question 16

If the patient is being ventilated via a mechanical ventilator via intermittent mandatory ventilation with partial ventilatory support, what would probably happen to PaCO₂ if the patient suddenly had no spontaneous breathing?

A) Increase
B) Decrease
C) Stay the same
D) Change according to FiO₂

Question 17

Physiological goals of artificial ventilatory support include which of the following?
1) Support or manipulate gas exchange.
2) Reduce or manipulate the work of breathing.
3) Increase lung volume.

A)1 and 2 only
B)2 and 3 only
C)1 and 3 only
D)1, 2, and 3

Question 18

Which of the following are advantages of Assist Control Volume ventilation?
1) Minimal safe level of ventilation achieved.
2) Patient can set breathing rate.
3) May reduce work of breathing.
4) Pressure is limited.

A)1 and 3 only
B)1, 2, and 3 only
C)3 and 4 only
D)2, 3, and 4 only

Question 19

After starting volume-cycled mechanical ventilation on a patient in respiratory failure with a V_T of 10 ml/kg, you measure and obtain a plateau pressure of 45 cm H₂O. Which of the following actions would you recommend to the patient's physician?

A) Decrease the inspiratory flow.
B) Lower the delivered V_T.
C) Administer a bronchodilator.
D) Add PEEP.

Question 20

What is the recommended range for the tidal volume for the initial ventilator settings in the volume control mode in a patient with normal lungs?

A) 4 to 6 ml/kg
B) 6 to 8 ml/kg
C) 10 to 12 ml/kg
D) 12 to 15 ml/kg

Question 21

Which of the following would decrease PaCO₂ when ventilating a patient using intermittent mandatory ventilation with pressure support?

A) Increase the level of pressure support.
B) Decrease the tidal volume.
C) Decrease the mechanical rate.
D) Increase the FiO_2.

Question 22

A physician orders intubation and mechanical ventilation in the synchronized intermittent mandatory ventilation mode for a 160-lb adult man with a history of chronic obstructive pulmonary disease. Which of the following settings would you recommend? Rate V_T

A) 12 breaths/min 500 ml
B) 15 breaths/min 550 ml
C) 20 breaths/min 300 ml
D) 16 breaths/min 500 ml

Question 23

A physician orders intubation and mechanical ventilation in volume-controlled ventilation mode for a 170-lb adult man with neuromuscular disease. Which of the following initial settings would you recommend? Rate V_T

A) 14 breath/min 540 ml
B) 20 breath/min 310 ml
C) 10 breath/min 770 ml
D) 6 breath/min 500 ml

Question 24

Patient's RR is 12 breaths/min, PaCO₂ is 60 mm Hg. If a PaCO₂ of 40 were desired, the RR be set at what value?

A) 18
B) 23
C) 35
D) 40

Question 25

In what scenario is pressure-controlled ventilation (PCV) most often used?

A) When limiting plateau pressure is needed
B) When a pneumothorax is present
C) When the patient has chronic obstructive pulmonary disease
D) When bilateral pneumonia is present

Question 26

What phrase is used to describe the situation where the patient with acute lung injury is ventilated with a smaller tidal volume and the PaCO₂ is allowed to increase above normal range to avoid additional lung injury?

A) Physiologic ventilation
B) Permissive hypercapnia
C) Adjusted ventilation
D) Dialed acidosis

Question 27

On a ventilator that has separate rate and minute ventilation (V_E) controls, the rate is set at 13/min and the V_E at 11 L/min. Approximately what V_T is the patient receiving?

A) 700 ml
B) 850 ml
C) 1000 ml
D) 1200 ml

Question 28

Which of the following statements is false regarding ventilation in the assist-control mode?

A) Every breath is supported by the ventilator.
B) Usually ensures a minimum safe level of ventilation is given.
C) Assist-control mode is typically applied using the volume control mode.
D) It is usually applied with a backup rate of 5 to 8 breaths/min.

Question 29

A physician orders intubation and mechanical ventilation in the continuous mandatory ventilation assist-control mode for a 125-lb adult woman with normal lungs. Which of the following initial settings would you recommend? Rate V_T

A) 10 breaths/min 550 ml
B) 14 breaths/min 400 ml
C) 18 breaths/min 450 ml
D) 12 breaths/min 470 ml

Question 30

Air trapping is a major concern in patients with what diagnosis when using the assist-control mode?

A) Pneumonia
B) Chronic obstructive pulmonary disease (COPD)
C) Chest trauma
D) Neuromuscular disease

Question 31

A ventilator has separate rate and V_T controls. If you set a V_T of 650 ml and a respiratory rate of 12/min in the continuous mandatory ventilation mode, what will the minute ventilation be?

A) 7800 ml/min (7.8 L/min)
B) 8500 ml/min (8.5 L/min)
C) 9600 ml/min (9.6 L/min)
D) 10,200 ml/min (10.2 L/min)

Question 32

Which of the following are used as alternative lung protective strategies in patients with ARDS?
1) Prone positioning
2) ECMO
3) High-frequency ventilation
4) Pressure support ventilation

A)1 and 3 only
B)1, 2, and 3 only
C)3 and 4 only
D)2, 3, and 4 only

Question 33

Which of the following statements is false regarding pressure-supported ventilation?

A) It is patient triggered, pressure limited, and flow cycled.
B) It can reduce the work of breathing during intermittent mandatory ventilation mode.
C) The usual range is 10 to 15 cm H₂O.
D) It is recommended for use in most patients in the intermittent mandatory ventilation (IMV) mode.

Question 34

For adolescents in the 8- to 16-year-old age range, which of the following ranges of ventilator setting would you initially recommend? Rate V_T

A) 12 to 20 breaths/min 6 to 8 ml/kg
B) 20 to 25 breaths/min 4 to 6 ml/kg
C) 25 to 35 breaths/min 8 to 10 ml/kg
D) 25 to 35 breaths/min 6 to 8 ml/kg

Question 35

Which of the following trigger levels is appropriate when setting a ventilator for pressure triggering?

A) 0.5 to 1.5 cm H₂O above the baseline pressure
B) 1.5 to 2.5 cm H₂O below the baseline pressure
C) 0.5 to 1.5 cm H₂O below the baseline pressure
D) 2.5 to 3.5 cm H₂O below the baseline pressure

Question 36

A ventilator has separate rate and minute ventilation controls. A physician orders continuous mandatory ventilation with a V_T of 550 ml at a respiratory rate of 12/min. What minute ventilation would you set on this ventilator?

A) 5500 ml/min (7.9 L/min)
B) 6600 ml/min (8.6 L/min)
C) 7400 ml/min (9.4 L/min)
D) 8400 ml/min (11.4 L/min)

Question 37

A physician orders intubation and mechanical ventilation in the continuous mandatory ventilation mode for a 200-lb predicted body weight (PBW) adult man with acute asthma exacerbation. Which of the following initial ventilator settings would you recommend? Rate V_T

A) 12 breaths/min 550 ml
B) 11 breaths/min 450 ml
C) 14 breaths/min 770 ml
D) 20 breaths/min 550 ml

Question 38

On some ventilators, which of the following can occur if a trigger setting is set too sensitive on a mechanical ventilator?

A) Autotriggering
B) Flow dyssynchrony
C) Barotrauma
D) Increased workload

Question 39

Which of the following are primary goals of mechanical ventilation?
1) Adequate alveolar ventilation (V_A)
2) Maintaining adequate hemoglobin levels
3) Restoring acid-base balance
4) Maintaining adequate alveolar oxygenation

A)1 and 3 only
B)1, 3, and 4 only
C)2 and 4 only
D)2, 3, and 4 only

Question 40

Which of the following statements are true regarding the use of controlled ventilation?
1) May allow the muscles of breathing to rest.
2) Can use larger 1:E ratio and may improve oxygenation.
3) Requires use of paralytic agents in spontaneously breathing patients.
4) Therapist has little control of needed inspiratory flow and pressure.

A)1 and 3 only
B)1, 2, and 3 only
C)3 and 4 only
D)2, 3, and 4 only

Question 41

Beneficial effects of using high inspiratory flows in patients with chronic airflow obstruction receiving flow-limited mechanical ventilation include which of the following?
1) Decreased work of breathing
2) Improved gas exchange
3) Decreased auto-PEEP

A)1 and 2 only
B)1 and 3 only
C)2 and 3 only
D)1, 2, and 3

Question 42

Which of the following is false about flow triggering of spontaneous breaths during mechanical ventilation?

A) Flow triggering lowers the patient's work of breathing.
B) Flow triggering is preferred for initiating spontaneous breaths.
C) Flow triggering reduces the work of breathing due to small endotracheal tubes.
D) Flow triggering results in better patient-ventilator synchrony.

Question 43

Which of the following would decrease PaCO₂ when ventilating a patient using intermittent mandatory ventilation with pressure support?

A) Increase the level of pressure support.
B) Decrease the tidal volume.
C) Decrease the mechanical rate.
D) Increase the FiO_2.

Question 44

In which of the following clinical situations is the incidence of auto-PEEP the greatest?
1) Patients with high respiratory rates
2) Intubated patients with obstructive lung disease
3) Patients with low minute volumes

A)1 and 2 only
B)1 and 3 only
C)2 and 3 only
D)1, 2, and 3

Question 45

Which of the following ventilator adjustments would decrease inspiratory time?
1) Increase the peak flow.
2) Increase the tidal volume.
3) Change the flow pattern from a decelerating wave to a square wave.

A)1 and 3 only
B)1 only
C)2 and 3 only
D)1, 2, and 3

Question 46

Which of the following trigger levels is appropriate when setting a ventilator for flow triggering?

A) 9 to 11 L/min below baseline flow
B) 7 to 9 L/min below baseline flow
C) 4 to 6 L/min below baseline flow
D) 1 to 2 L/min below baseline flow

Question 47

What flow pattern is least optimal for ventilating a patient with cardiovascular instability?

A) Accelerating flow pattern
B) Square flow pattern
C) Decelerating flow pattern
D) Constant flow pattern

Question 48

When starting flow-limited ventilatory support on an adult patient, which of the following inspiratory flow settings would you initially select?

A) 60 L/min
B) 50 L/min
C) 40 L/min
D) 30 L/min

Question 49

An adult patient in respiratory failure has the following blood gases on a nasal cannula at 5 L/min: pH = 7.20; PaCO₂ = 67 mm Hg; HCO₃^-= 27 mEq/L; PaO₂ = 89 mm Hg. The attending physician orders intubation and ventilatory support. What FiO₂ would you recommend to start with?

A) 0.21
B) 0.30
C) 0.50
D) 0.90

Question 50

When adjusting the FiO₂ setting for a patient receiving mechanical ventilatory support, what should your goal be?

A) Decrease the FiO₂ to below 0.70 as soon as possible.
B) Maintain the highest possible FiO₂ as long as needed.
C) Decrease the FiO₂ to below 0.30 as soon as possible.
D) Decrease the FiO₂ to below 0.50 as soon as possible.

Question 51

Which of the following is false about flow-triggered ventilatory support?

A) The work of breathing with flow triggering is less than with pressure triggering.
B) Flow-triggered systems respond to changes in flow rather than pressure.
C) Pressure triggering on new ventilators may be as sensitive as flow-triggering.
D) Flow triggering will decrease the work of breathing in patients with small endotracheal tubes and auto-PEEP.

Question 52

Which of the following criteria represents the recommended starting point for considering the use of PEEP?

A) PaO₂ less than 40 to 50 on FiO₂ greater than 0.80 - 1.0
B) PaO₂ less than 50 to 60 on FiO₂ greater than 0.40 - 0.50
C) PaO₂ less than 100 on FiO₂ of 1.0
D) PaO₂ less than 50 on FiO₂ greater than 0.75

Question 53

In which of the following conditions is PEEP likely to be useful?
1) ARDS
2) Pulmonary edema
3) Acute lung injury
4) Neuromuscular disease

A)1 and 3 only
B)1, 2, and 3 only
C)3 and 4 only
D)2, 3, and 4 only

Question 54

Immediately after cardiac arrest and resuscitation, a patient is placed on a ventilator in the continuous mandatory ventilation assist-control mode. What initial FiO₂ would you recommend?

A) 1.0
B) 0.8
C) 0.6
D) 0.4

Question 55

To prevent atelectasis and improve gas exchange, most thoracic surgery patients placed on ventilatory support receive which of the following?

A) 0 cm H₂O PEEP
B) 5 cm H₂O PEEP
C) 8 cm H₂O PEEP
D) 10 cm H₂O PEEP

Question 56

A chronic obstructive pulmonary disease (COPD) patient receiving ventilatory support in the CMV assist-control mode at a rate of 14 and a V_T of 750 ml exhibits clinical signs of air trapping. Which of the following would you recommend to correct this problem?
1) Decrease "E" time.
2) Increase the inspiratory flow rate.
3) Decrease the assist-control rate.

A)1 and 2 only
B)1 and 3 only
C)2 and 3 only
D)1, 2, and 3

Question 57

For adults with otherwise normal lungs who are receiving ventilatory support in the continuous mandatory ventilation control or assist-control mode, inspiratory flow should be set to provide what 1:E?

A) 2:1
B) 3:1
C) 1:1
D) 1:2

Question 58

A patient receiving continuous mandatory ventilation in the assist-control mode develops auto-PEEP. Which of the following changes in ventilatory patterns would you consider to minimize the effects of auto-PEEP in this patient?
1) Decreasing the rate or increasing V_T
2) Using low-rate synchronized intermittent mandatory ventilation
3) Decreasing the peak inspiratory flow
4) Lowering the V_T and letting the PaCO2 rise

A)2 and 4 only
B)3 and 4 only
C)1, 2, and 3 only
D)1, 2, and 4 only

Question 59

A patient receiving continuous mandatory ventilation in the assist-control mode develops auto-PEEP. Which of the following general approaches would you consider to minimize the effects of auto-PEEP in this patient?
1) Increasing expiratory time
2) Applying PEEP
3) Switching ventilating mode to synchronized intermittent mandatory ventilation

A)1 and 2 only
B)1 and 3 only
C)2 and 3 only
D)1, 2, and 3

Question 60

Which of the following statements is false regarding the use of an inspiratory pause during mechanical ventilation?

A) It may be useful in ARDS patients.
B) It may be useful when obtaining a chest radiograph.
C) It has been shown to increase effectiveness of bronchodilator therapy.
D) It will increase mean airway pressure.

Question 61

Indications for delivering sigh breaths during mechanical ventilation include which of the following?
1) Before and after suctioning
2) During chest physical therapy
3) In patients with stiff lungs
4) When small V_T values are used

A)1 and 3 only
B)1, 2, and 4 only
C)2 and 4 only
D)2, 3, and 4 only

Question 62

A chronic obstructive pulmonary disease (COPD) patient in respiratory failure is receiving ventilatory support in the volume-targeted intermittent mandatory ventilation mode at a rate of 6/min. You measure an auto-PEEP level of 9 cm H₂O. Which of the following would you recommend to decrease the effects of auto-PEEP in this patient?

A) Decreasing the rate and increasing V_T.
B) Lowering the V_T and letting the PaCO₂ rise.
C) Applying 4 to 6 cm H₂O PEEP.
D) Decreasing the peak inspiratory flow.

Question 63

When setting the tidal volume on a patient being mechanically ventilated, what criteria should be kept in mind?

A) It should never cause the plateau pressure to exceed 28 mm Hg.
B) It should never cause the peak pressure to exceed 35 mm Hg.
C) It should result in the static pressure of less than 10 mm Hg.
D) It should result in a peak pressure of no more than 25 mm Hg.

Question 64

If available, the FiO₂ alarm should be set to what percentage?

A) ±3%
B) ±5%
C) ±8%
D) ±10%

Question 65

A patient suffering from postoperative complications has been receiving mechanical ventilation for 6 days with a volume ventilator. A heat-moisture exchanger (HME) is providing control over humidification and airway temperature. Over the past 24 hr, the patient's secretions have decreased in quantity but are thicker and more purulent. Which of the following actions would you suggest at this time?

A) Replace the HME.
B) Switch over to a heated wick humidifier.
C) Administer acetylcysteine every 2 hr via the nebulizer.
D) Increase the frequency of suctioning.

Question 66

You have just placed a chronic obstructive pulmonary disease (COPD) patient on intermittent mandatory ventilation at a rate of 8/min, a V_T of 550 ml, and an FiO₂ of 0.40. To ensure proper equilibration between the alveolar and arterial gas tensions, how long should you wait before drawing a sample for measurement of the ABG?

A) 5 min
B) 10 min
C) 15 min
D) 30 min

Question 67

After placing a patient on a volume-cycled ventilator in the continuous mandatory ventilation assist-control mode, you note that 55 cm H₂O pressure is required to deliver the preset V_T of 950 ml. What high-pressure limit would you now set for this patient?

A) 60 cm H₂O
B) 70 cm H₂O
C) 80 cm H₂O
D) 90 cm H₂O

Question 68

When adjusting a patient's oxygenation during mechanical ventilatory support, what should your goal be?

A) SaO₂ of 80% to 90%
B) PaO₂ of 100 to 150 mm Hg
C) SaO₂ of 95% to 100%
D) PaO₂ of 60 to 100 mm Hg

Question 69

Which of the following criteria should be met before considering use of a heat-moisture exchanger (HME) for a patient being placed on ventilatory support?
1) There should be no problem with retained secretions.
2) The patient should not have fever (normothermic).
3) The patient should be adequately hydrated.
4) The support should be short term (24 to 48 hr).

A)1, 2, and 3 only
B)2 and 4 only
C)1, 2, 3, and 4
D)3 and 4 only

Question 70

What limits should be initially set for high and low V_T values and/or minute volume alarms on a ventilatory support device?

A) ±5% to 10%
B) ±10% to 15%
C) ±15% to 20%
D) ±20% to 25%

Question 71

When the therapist is initially setting the high-pressure alarm on the ventilator and the patient's plateau pressure is less than 30 cm H₂O, what should the high-pressure alarm be set at?

A) 5 to 10 cm H₂O above the peak pressure
B) 10 to 20 cm H₂O above the peak pressure
C) 10 to 12 cm H₂O above the plateau pressure
D) 10 to 15 cm H₂O above the mean airway pressure

Question 72

When using a heated humidifier during mechanical ventilation, the inspired gas temperature at the airway should be set to what level?

A) 29° to 31° C
B) 31° to 35° C
C) 35° to 37° C
D) 38° to 40° C

Question 73

For which of the following patients requiring ventilatory support would you recommend against using a heat-moisture exchanger (HME) for airway humidification?
1) Patient with an expired V_T less than 70% of the delivered V_T
2) Patient with a spontaneous minute ventilation of 14 L/min
3) Patient with body temperature less than 32° C

A)1 and 2 only
B)1 and 3 only
C)2 and 3 only
D)1, 2, and 3

Question 74

What is the predicted change in tidal volume by adding 6 in of tubing to a ventilator circuit?

A) Decrease of 50 to 70 ml
B) Decrease of 30 to 50 ml
C) Decrease of 20 to 30 ml
D) No change

Question 75

Which of the following would you initially verify in assessing the airway of a patient placed on ventilatory support?
1) Cuff pressure
2) Tube position
3) Tube patency

A)1 and 2 only
B)1, 2, and 3
C)1 and 3 only
D)2 and 3 only

Question 76

A heat-moisture exchanger (HME) should be avoided in which of the following circumstances?
1) Patients with excessive secretions
2) Patients with a high FiO₂
3) Patients with low body temperature

A)1 only
B)1 and 2 only
C)1 and 3 only
D)1, 2, and 3

Question 77

A dehydrated, feverish patient suffering from acute bacterial pneumonia is being intubated in order to provide mechanical ventilatory support. Which of the following devices would you select to control humidification and airway temperature for this patient?

A) Unheated large-volume wick humidifier
B) Heated wick humidifier with servo-control
C) Large-reservoir, high-output heated jet nebulizer
D) Heat-moisture exchanger

Question 78

After setting up a patient on a ventilatory support device, which of the following supplementary equipment would you require to be available at the bedside?
1) Suction source and catheters
2) Backup artificial airway
3) Manual resuscitator with O₂

A)2 and 3 only
B)1 and 2 only
C)1, 2, and 3
D)1 and 3 only

Question 79

Which of the following would you assess immediately after a patient is placed on a ventilatory support device?
1) ABGs
2) Patient's airway
3) Patient's vital signs

A)1 and 2 only
B)1 and 3 only
C)2 and 3 only
D)1, 2, and 3

Question 80

When titrating the FiO₂ level downward from 100% to 40%, what is the maximum increment that should be applied between estimates of oxygenation?

A) 5%
B) 10%
C) 20%
D) 25%