This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Traumatic Brain Injury, Subject name: Surgery
[{'content': 'Most common cause of non traumatic subarachnoid hemorrhage - \nSelect and explain. \nA. Idiopathic, B. Berry aneurysm rupture, C. Hypertension, D. AV malformation', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Berry aneurysm o Excluding head trauma, most common cause of subarachnoid hemorrhage is rupture of a saccular (Berry) aneurysm.", 'role': 'assistant'}]