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': 'In optic neuritis the best investigation to be done includes: \nSelect and explain. \nA. Goldman perimetery, B. Keratoscopy, C. Ophthalmoscopy, D. Opthalmodynamometery', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. Goldman perimetery', 'role': 'assistant'}]