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': 'Chicken pox is infective \nSelect and explain. \nA. 2 days before and 5 days after rash appearance, B. 2 days before and 2 days after rash appearance, C. 4 days before and 4 days after rash appearance, D. 4 days before and 5 days after rash appearance', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]