Airway Resistance (R_aw) Is Usually Defined As

Airway resistance (R_aw) is usually defined as:

A) the pressure difference between the ends of the airway divided by the flow rate of gas moving through the airway.
B) the sum of the pressures between the ends of the airway divided by the flow rate of gas moving through the airway.
C) the pressure difference between the ends of the airway multiplied by the flow rate of gas moving through the airway.
D) the sum of the pressures between the ends of the airway multiplied by the flow rate of gas moving through the airway.