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': 'The pa most commonly involved in Otosclerosis is: \nSelect and explain. \nA. Oval window, B. Round window, C. Tympanic membrane, D. Malleus', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Oval window', 'role': 'assistant'}]