This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Larynx, Subject name: ENT
[{'content': 'Most common organism causing laryngotracheobronchitis is \nSelect and explain. \nA. RSV, B. Para-influenza virus, C. Influenza virus, D. H. Influenza', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Para-influenza virus I and II is the most common organism causing laryngotracheobronchitis. Ref: Textbook of diseases of ENT, PL Dhingra, 7th edition, pg no. 328', 'role': 'assistant'}]