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
The commonest extradural spinal tumour is - 
Select and explain. 
A. Neurofibroma, B. Glioma, C. Meningioma, D. Metastasis
D: Metastasis
Answer: D: Metastasis 
Explanation: • MC spinal tumor: Metastasis
• MC primary spinal tumor: Nerve sheath tumor
• MC intramedullary tumor: Astrocytoma
• MC site of primary spinal tumor: Intradural extramedullary