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: Biochemistry
[{'content': 'The main enzyme responsible for activation of xenobiotics is (detoxification) \nSelect and explain. \nA. Cytochrome P-450, B. Glutathione S-transferase, C. NADPH cytochrome P-450-reductase, D. Glucuronyl transferase', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]