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': 'Communication between middle ear and Eustachian tube is obliterated in which surgery? \nSelect and explain. \nA. Tympanoplasty, B. Schwaz operation, C. Modified radical mastoidectomy, D. Radical mastoidectomy', 'role': 'user'}, {'content': 'Answer: D \nExplanation: In radical mastoidectomy, the opening of Eustachian tube is closed by curetting its mucosa and plugging the opening with tensor tympani muscle or cailage.', 'role': 'assistant'}]