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': 'Prior H/O ear surgery Scanty, foul smelling, painless discharge from the ear is characteristic feature of which of the following lesions - \nSelect and explain. \nA. ASOM, B. Cholesteatoma, C. Central perforation, D. Otitis externa', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Cholesteatoma / attico antral type of CSOM / marginal perforation is characterised by scanty foul smelling, painless discharge from the ear. The foul smell is due to saprophytic infection and osteitis', 'role': 'assistant'}]