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': 'Which is the best parameter for analysis of Hypoxic hypoxia: \nSelect and explain. \nA. Aerial PO2, B. Aerial PCO2, C. Venous PO2, D. A-V Difference', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. Aerial PO2.', 'role': 'assistant'}]