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
Most effective method of assessing breathing is by measuring: 
Select and explain. 
A. Tidal volume, B. Respiratory rate, C. Alveolar ventilation, D. FEV 1
D: FEV 1
Answer: D: FEV 1 
Explanation: None