This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
In chronic renal failure which one is contraindicated? 
Select and explain. 
A. Furosenmide, B. Ethacrynic acid, C. Triamterenc, D. Bumetanide
C: Triamterenc
Answer: C: Triamterenc 
Explanation: Ans. is 'c' Triamterene o K+ spring diuretics can cause serious hyperkalemia when renal function is inadequate.