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': 'Most common site of cerebral aneurysm is: \nSelect and explain. \nA. Anterior communicating aery, B. Posterior communicating aery, C. Middle cerebral aery, D. None of the above', 'role': 'user'}, {'content': "Answer: A \nExplanation: Prevalence of Cerebral Aneurysm by Location: Anterior circulation 85% 30% Anterior communicating aery 25% Posterior communicating aery 20% Middle cerebral aery bifurcation 10% Other Posterior circulation 15% 10% Basilar aery, most frequently at the basilar tip 5% Veebral aery, usually at the posterior inferior cerebellar aery Ref: Schwaz's principle of surgery 9th edition, chapter 42.", 'role': 'assistant'}]