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': 'Functional assessment of optic nerve is by: \nSelect and explain. \nA. Angiography, B. Fundoscopy, C. Perimetry, D. CT Scan', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. Perimetry', 'role': 'assistant'}]