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': 'Maximum refraction takes place between \nSelect and explain. \nA. Air tear film, B. Tear film and cornea, C. Cornea and aqueous, D. Aqueous lens', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ansa. Air tear film', 'role': 'assistant'}]