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: ENT
[{'content': 'Commonest cause of acute otitis media in children is - \nSelect and explain. \nA. H. influenza, B. Strepto-pneumoniae, C. Staph aureus, D. Pseudomonas', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]