This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Lens, Subject name: Ophthalmology
[{'content': 'Which of the following prevent lens opacity by free radical scavening? \nSelect and explain. \nA. Glutathione, B. Catalase, C. Vitamin A, D. Vitamin E', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Glutathione prevent lens opacity by free radical scavening.', 'role': 'assistant'}]