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': 'Infectivity period of chicken pox \nSelect and explain. \nA. 2 days before & 5 days after appearance of rash, B. 1 week before & 1 week after onset of rash, C. Till the fever subsides, D. 10 days after onset of rash', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Infectivity period of chicken pox is 2 days before & 5 days after onset of rash.', 'role': 'assistant'}]