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': 'What is the window period in a case of HIV infection ? \nSelect and explain. \nA. 3 weeks, B. 3 months, C. 6 months, D. 1 year', 'role': 'user'}, {'content': 'Answer: B \nExplanation: "Window period" of HIV is immediately after the acquisition of infection, during which serology may be negative. This period typically lasts from 3 weeks to 3 months. Non-serologic tests can be employed to cover this period. Tests to detect HIV during window period: p24 antigen testing, nucleic acid testing.', 'role': 'assistant'}]