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: Social & Preventive Medicine
[{'content': 'Window period for HIV infection is \nSelect and explain. \nA. 3-12 weeks, B. 8-20 weeks, C. 6-24 weeks, D. None', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]