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': 'Trough shaped curve in audiometry is seen in - \nSelect and explain. \nA. Congenital SNHL, B. Otitis media, C. Otosclerosis, D. Acoustic neuroma', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]