This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nutrition and Health, Subject name: Social & Preventive Medicine
[{'content': 'Milk is deficient in:(1994) \nSelect and explain. \nA. Calcium, B. Vitamin A, C. Vitamin D, D. Iron', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans: dRef: Park, 17th ed, p. 429, Table (21) & 18th ed, p. 455, Table (21)', 'role': 'assistant'}]