Which of the Following Statements Best Describes the Function of Proportional

Which of the following statements best describes the function of proportional assist ventilation on the Covidien PB 840?

A) The percentage of the work done by the patient is adjusted by the ventilator monitoring the work of breathing.
B) The percentage of the work done by the ventilator is automatically reduced as the compliance and resistance is improving.
C) The operator sets a percentage of the work of breathing that is done by the ventilator; the remainder of the work of breathing is done by the patient.
D) The ventilator adjusts the amount of work done by the ventilator based on continuous monitoring of the partial pressure of end-tidal carbon dioxide and the oxygen saturation measured by pulse oximeter.