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
Wof vitamin D preparations would be the most appropriate in a patient with poor renal function 
Select and explain. 
A. Cholecalciferol, B. Calcitriol, C. Ergocalciferol, D. Calcifediol
B: Calcitriol
Answer: B: Calcitriol 
Explanation: 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