This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.N.S, Subject name: Medicine
[{'content': 'The common cause of subarachnoid hemorrhage Is \nSelect and explain. \nA. Aerio-venous malformation, B. Cavernous angioma, C. Aneurysm, D. Hypeension', 'role': 'user'}, {'content': 'Answer: C \nExplanation: *Subarachnoid hemorrhage commonly,but exclusively results from rupture of congenital berry aneurysms in the interpeduncular cistern . Subarachnoid haemorrhage, a medical emergency, is usually from a bulging blood vessel that bursts in the brain (aneurysm). It may lead to permanent brain damage or death if not treated promptly Ref Harrison20th edition pg 2567', 'role': 'assistant'}]