This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cerebrovascular, Subject name: Medicine
[{'content': 'Most common cause of subarachnoid hemorrhage is: \nSelect and explain. \nA. Hypertension, B. Berry aneurysm, C. Intracranial tumors, D. Arterio-venous malformations (AVM)', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' Berry aneurysm [Reference Harrison 17/e p 1726-1728 & 16/e page 2390, 2388 (15th/e page 2388)1Actually head trauma is the most common cause of subarachnoid hemorrhage.Rupture of berry (Saccular) aneurysm is the 2nd most common cause of subarachnoid hemorrhage, but among the given options it is the most common.", 'role': 'assistant'}]