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: Surgery
[{'content': 'The commonest extradural spinal tumour is - \nSelect and explain. \nA. Neurofibroma, B. Glioma, C. Meningioma, D. Metastasis', 'role': 'user'}, {'content': 'Answer: D \nExplanation: • MC spinal tumor: Metastasis\n• MC primary spinal tumor: Nerve sheath tumor\n• MC intramedullary tumor: Astrocytoma\n• MC site of primary spinal tumor: Intradural extramedullary', 'role': 'assistant'}]