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': 'Residual volume of lung is defined as: March 2013 \nSelect and explain. \nA. Additional volume of air that can be inspired forcefully after the end of normal inspiration, B. Volume of air breathed out of lungs in a single normal quiet respiration, C. Additional volume of air that can be expired forcefully after normal expiration, D. Volume of air remaining in lungs even after forced expiration', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. D i.e. Volume of air remaining in lungs even after forced expiration', 'role': 'assistant'}]