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
Normal inspiratory reserve volume (IRV) is ? 
Select and explain. 
A. 500 ml, B. 1200 ml, C. 3000 ml, D. 4900 ml
C: 3000 ml
Answer: C: 3000 ml 
Explanation: Ans. is 'c' i.e., 3000 ml(Ref: Ganong 24e/e p.629)