This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Pharmacology
[{'content': 'Wof vitamin D preparations would be the most appropriate in a patient with poor renal function \nSelect and explain. \nA. Cholecalciferol, B. Calcitriol, C. Ergocalciferol, D. Calcifediol', 'role': 'user'}, {'content': 'Answer: B \nExplanation: 1-Hydroxylase activity must be adequate to produce 1,25(OH) 2 D 3. Calcitriol is the only choice that is already 1-hydroxylated. Ref:- kd tripathi; pg num:-341', 'role': 'assistant'}]