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': 'One millimeter increase in the radius of curvature of cornea leads to hypermetropia of: \nSelect and explain. \nA. 3 dioptres, B. 4 dioptres, C. 5 dioptres, D. 6 dioptres', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. 6 dioptres', 'role': 'assistant'}]