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': 'Which does NOT handle free radicals inside the lens \nSelect and explain. \nA. Vitamin A, B. Vitamin C, C. Vitamin E, D. Catalase', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Preventive antioxidant mechanisms of the lens against free radicals are:\n\nEnzymatic defence mechanism - reduced glutathione, glutathione peroxide, superoxide dismutase and catalase\nNon-enzymatic defence mechanism - vitamin C, vitamin E and carotenoids', 'role': 'assistant'}]