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': 'Otosclerosis typically begins at: \nSelect and explain. \nA. Scutum, B. Round window, C. Tympanic membrane, D. Fossa antefenestrum', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Fossa antefenestrum', 'role': 'assistant'}]