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': 'Xerosis is seen in: September 2006 \nSelect and explain. \nA. Vitamin A deficiency, B. Vitamin B deficiency, C. Vitamin C deficiency, D. Vitamin D deficiency', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. A: Vitamin A deficiency', 'role': 'assistant'}]