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': 'A decrease in the arterial PO2 is seen in: \nSelect and explain. \nA. Decrease in hemoglobin concentration of arterial blood, B. Paralysis of inspiratory muscles, C. Sluggish blood flow, D. High altitudes', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]