This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nutrition, Subject name: Pediatrics
[{'content': 'Stage X3B refers to the following in the classification of vitamin A deficiency: \nSelect and explain. \nA. Night blindness, B. Corneal xerosis, C. Conjunctival xerosis, D. Keratomalacia', 'role': 'user'}, {'content': "Answer: D \nExplanation: d. Keratomalacia(Ref: Nelson's 20/e p 3 IB-320, Ghai B/e p 111-112)WHO classification of Vitamin A deficiency:IndicatorCategoryNight blindnessXNConjunctival xerosisX1ABitot's spotsX1BCorneal xerosisX2Corneal ulcerationX3AKeratomalaciaX3BXerophthalmia-related corneal scarsXS", 'role': 'assistant'}]