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': 'Bitots spots are seen in: March 2004 \nSelect and explain. \nA. Vitamin D deficiency, B. Vitamin A deficiency, C. Vitamin E deficiency, D. Vitamin B6 deficiency', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B i.e. Vitamin A deficiency', 'role': 'assistant'}]