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': 'A female presented with severe headache of sudden onset. On CT scan a diagnosis of subarachnoid heamorrhage is made. The most common site of subarachnoid haemorrhage is - \nSelect and explain. \nA. Middle meningeal aery, B. Berry aneurysm rupture, C. Basilar aery, D. Subdural venous sinuses', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. is \' b\' ie. Berry Aneurysm rupture "Excluding head trauma the most common cause of SAH is rupture of a saccular aneurysm (Berry aneurysm or congenital aneurysm)."', 'role': 'assistant'}]