This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Optics and Errors of Refraction, Subject name: Ophthalmology
[{'content': 'Maximum refraction is done by: \nSelect and explain. \nA. Anterior surface of lens, B. Posterior surface of lens, C. Anterior surface of cornea, D. Posterior surface of cornea', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Power of eye is contributed by surfaces where refraction of light occurs as it traverses from the external environment to the retina. These are: - Anterior surface of cornea ( max contribution) - Posterior surface of cornea - Anterior surface of lens - Posterior surface of lens', 'role': 'assistant'}]