This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pharmacology
DPP4 inhibitor requiring dose reduction in both liver and kidney failure 
Select and explain. 
A. Linagliptin, B. Sitagliptin, C. Saxagliptin, D. Vildagliptin
D: Vildagliptin
Answer: D: Vildagliptin 
Explanation: Vildagliptin require and of both reductions in liver and kidney failure.Ref: KDT 7TH/275