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': 'The commonest cranial nerve palsy in tabes dorasalis is: \nSelect and explain. \nA. III nerve, B. IV nerve, C. VI nerve, D. Total ophthalmoplegia', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. III nerve', 'role': 'assistant'}]