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
Drug used in renal osteodystrophy: 
Select and explain. 
A. Vitamin D, B. Calcitriol, C. Calcifediol, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: Ans. (d) All of the aboveRef. Katzung 9th ed. /1028* Vitamin D has been used in treating renal osteodystrophy* In mild forms of malabsorption, vitamin D should suffice to raise serum levels of 25(OH) D into the normal range. Many patients with severe disease do not respond to vitamin D.* Calcitriol and Calcifediol have been used successfully in treatment of renal osteodystrophy and intestinal osteodystrophy.