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: Microbiology
[{'content': 'Half-life of free HIV in plasma is: \nSelect and explain. \nA. 24 hours, B. 6 hours, C. 12 hours, D. 3 months', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]