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': "Type 'C' tympanogram is seen in \nSelect and explain. \nA. Serous Otitis media, B. Otosclerosis, C. Ossiullor discontinuity, D. Eustachian Tube blockade", 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]