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
[{'content': 'Functional residual capacity of lung is defined as \nSelect and explain. \nA. Volume expired after normal expiration, B. Volume remaining after forced expiration, C. ERV + RV, D. Tidal volume + volume inspired forcefully', 'role': 'user'}, {'content': 'Answer: C \nExplanation: The amount of air that remains in lung after a normal expiration.', 'role': 'assistant'}]