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
Which drug abolishes coicomedullary osmotic gradient ? 
Select and explain. 
A. Furosemide, B. Thiazide, C. Spironolactone, D. Triamterene
A: Furosemide
Answer: A: Furosemide 
Explanation: Ans. is'a'i.e., Furosemide (Ref. KDT p. 579)Furosemide (Frusemide)It is a high ceiling (loop) diuretic which inhibits of Na+-K+-2cl- cotranspoer.The coicomedullary osmotic gradient is abolished and positive as well as negative free water clearance is blocked.K+ excretion is increased mainly due to high Na+ load reaching DT.