This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ear, Subject name: ENT
[{'content': 'C-shaped curve on tympanometry is seen in \nSelect and explain. \nA. Serous otitis media, B. Otosclerosis, C. TM perforation, D. Eustachian tube obstruction', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Type C: Max compliance occurs with negative pressure in excess of 100mm H2O Seen in retracted TM Also some fluid present in the middle ear. Ref: Dhingra; 6th Edition; pg no 24', 'role': 'assistant'}]