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: Anatomy
[{'content': 'Contents of the middle car cavity are all except: \nSelect and explain. \nA. Malleus, B. Stapes, C. Chorda tympani, D. Cells of cord', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]