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: Anatomy
[{'content': 'Which nerve is compressed by aneurysm of posterior communicating artery in circle of willis \nSelect and explain. \nA. Hypophysis cerebri, B. Trochlear nerve, C. Oculomotor nerve, D. Optic nerve', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]