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': '4 months old infant had respiratory distress.It was diagnosed as bronchiolitis. most common cause of this is \nSelect and explain. \nA. Measles, B. Respiratory syncytial virus, C. Influenza, D. Para Influenza virus', 'role': 'user'}, {'content': 'Answer: B \nExplanation: RSV is the m/c cause of lower respiratory tract infection below 1 year.', 'role': 'assistant'}]