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': 'Flat & dome shaped graph in tympanogram is found in - \nSelect and explain. \nA. Oto sclerosis, B. Ossicular discontinuity, C. TM perforation, D. Middle ear fluid', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]