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': 'The most potent form of vitamin D is \nSelect and explain. \nA. Ergocalciferol (Vit. D2), B. 7 dihydroxy cholecalciferol, C. 25 dihydroxy cholecalciferol, D. 1,25 dihydroxy cholecalciferol', 'role': 'user'}, {'content': 'Answer: D \nExplanation: 1,25 dihydroxy cholecalciferol is the metabolically active form of vitamin D. It helps in the absorption of calcium and phosphorus in the gut, and promotes bone dissolution and mineralization, thereby increasing serum calcium and alkaline phosphatase activity. Ref: Page 127; Ghai essential pediatrics; 6th edition', 'role': 'assistant'}]