This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Physiology
Functional residual capacity represents the volume of air remaining in lungs 
Select and explain. 
A. After forceful expiration, B. After forceful inspiration, C. After normal inspiration, D. After normal expiration
D: After normal expiration
Answer: D: After normal expiration 
Explanation: Functional residual capacity * Functional residual capacity is the volume of air remaining in the lungs after expiration of a normal breath * Normal value - 2.5 L * (Residual volume + Expiratory reserve volume) Ref:- Ganong's Review of Medical Physiology 25th ed; pg num:- 629