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: Medicine
Disproportionately 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. Hypovolumia
C: Intrinsic renal failure
Answer: C: Intrinsic renal failure 
Explanation: None