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': 'Tympanoplasty is mainly used for- \nSelect and explain. \nA. Otosclerosis, B. CSOM, C. ASOM, D. None', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., CSOM o Myringoplasty' and tympanoplasty are mainly used in tubotympanic type of CSOM when there is recurring discharge or if there is deafness sufficient to cause disability'.", 'role': 'assistant'}]