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: Medicine
[{'content': "Most common cause of hypoxemia is- \nSelect and explain. \nA. Lowered inspired PO2, B. Hypoventilation, C. 'Ventialtion perfusion mismatch, D. Decreased diffusing capacity", 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]