This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pathology
[{'content': 'Highest refractory of index is at \nSelect and explain. \nA. Ant surface of cornea, B. Post surface of cornea, C. Center of lens, D. Posterior capsule of lens', 'role': 'user'}, {'content': 'Answer: C \nExplanation: .', 'role': 'assistant'}]