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': 'Cranial nerve most commonly involved in posterior communicating aery aneurysm is \nSelect and explain. \nA. Oculomotor, B. Facial, C. Optic, D. Trigeminal', 'role': 'user'}, {'content': 'Answer: A \nExplanation: . *a third nerve palsy may be present due to local pressure from an aneurysm of the posterior communicating aery. Ref Harrison20th edition pg 2456', 'role': 'assistant'}]