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: Medicine
[{'content': 'Cranial nerve most commonly involved in posterior communicating artery aneurysm is - \nSelect and explain. \nA. Oculomotor, B. Facial, C. Optic, D. Trigeminal', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]