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': 'Not an anti oxidant in Lens \nSelect and explain. \nA. Vitamin A, B. Vitamin B, C. Vitamin C, D. Vitamin D', 'role': 'user'}, {'content': 'Answer: A \nExplanation: β Carotenoids (precursor of Vitamin A)\xa0is an anti oxident in Lens, not Vitamin A.', 'role': 'assistant'}]