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': 'Paralysis of 3rd, 4th, 6th, nerves with involvement of ophthalmic division of 5th nerve, localizes the lesion to - \nSelect and explain. \nA. Cavernous sinus, B. Apex of orbit, C. Brainstem, D. Base of skull', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Cavernous sinus lesions may be associated with paralysis of 3rd, 4th, 5th (ophthalmic and maxillary divisions) and 6th nerve on account of its characteristic relations.', 'role': 'assistant'}]