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 decrease in axial length of the eyeball leads to hypermetropia of: \nSelect and explain. \nA. 6 dioptres, B. 2 dioptres, C. 3 dioptres, D. 4 dioptres', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. 3 dioptres', 'role': 'assistant'}]