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': 'Most common agent responsible for bronchiolitis is \nSelect and explain. \nA. RSV, B. Adenovirus, C. Herpesvirus, D. Influenza virus', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]