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: Ophthalmology
[{'content': 'Isolated painful third nerve palsy is a feature of aneurysms of: \nSelect and explain. \nA. Posterior communicating aery, B. Anterior communicating aery, C. Veebrobasillary aery, D. Ophthalmic aery', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. Posterior communicating aery', 'role': 'assistant'}]