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': 'Cholesteatoma occurs in: \nSelect and explain. \nA. CSOM with central perforation, B. Masked mastoiditis, C. Coalescent mastoiditis, D. Acute necrotising Otitis media', 'role': 'user'}, {'content': 'Answer: D \nExplanation: (d) Acute necrotising Otitis media(Ref. Cummings, 6th ed., 2146)The MC route of secondary cholesteatoma is migration of keratinising stratified squamous epithelium through marginal perforation of TM.This marginal perforation follows ANOM.Rest of the choices are not associated with cholesteatoma.', 'role': 'assistant'}]