This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
The forced vital capacity is 
Select and explain. 
A. The amount of air that normally moves into (or out of) the lung with each respiration., B. The amount of air that enters the lung but does not participate in gas exchange., C. The largest amount of air expired after maximal inspiratory effort., D. The largest amount of gas that can be moved into and out of the lungs in 1 min.
C: The largest amount of air expired after maximal inspiratory effort.
Answer: C: The largest amount of air expired after maximal inspiratory effort. 
Explanation: The forced vital capacity (FVC), the largest amount of air that can be expired after a maximal inspiratory effort, is frequently measured clinically as an index of pulmonary function.