Ans: B. Linagliptin(Ref Goodman Gilman 12/e p1264; Katzung 13/e p740, 12/e p761; FDA website: http://wwwfda.gov/ Safety/ MedWatch/Safetylnformation/ircm3 I 9215.htm)Linagliptin:Given safely in renal failure.Chronic kidney disease:Major complication in type 2 diabetes.Metformin usage is challenging.More severe renal disease - Less likely for metformin use.Due to safety concerns.