This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other topics and Adverse effects, Subject name: Anatomy
[{'content': 'A child Mahesh has been diagnosed to be having vitamin D dependent rickets. The most appropriate vitamin D preparation for him is: \nSelect and explain. \nA. Calciferol, B. Cholecalciferol, C. Calcifediol, D. Calcitriol', 'role': 'user'}, {'content': 'Answer: D \nExplanation: (Ref: KDT 6/e p390) Most active vitamin D preparation is calcitriol.', 'role': 'assistant'}]