This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Kidney, Subject name: Medicine
Dispropoionately increased blood urea levels compared to serum creatinine (urea creatinine ratio 20:1) can be seen in the following except - 
Select and explain. 
A. Prerenal failure, B. CCF, C. Intrinsic renal failure, D. Hypovolemia
C: Intrinsic renal failure
Answer: C: Intrinsic renal failure 
Explanation: Intrinsic or intrarenal acute renal failure (ARF) occurs when direct damage to the kidneys causes a sudden loss in kidney function. The most common causes of intrinsic acute renal failure are acute tubular necrosis (ATN), acute glomerulonephritis (AGN), and acute interstitial nephritis (AIN) . Ref Harrison20th edition pg 236