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
[{'content': 'Plasma urea / creatinine ratio of 20:1 may be seen in: \nSelect and explain. \nA. Rhabdomyolysis, B. Ureteric calculi, C. Pre-renal failure, D. Chronic Glomerulonephritis', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Plasma urea/creatinine ratio of 20:1 is seen in renal azotemia. In renal failure both BUN and creatinine levels are elevated, and the ratio is elevated as filtered urea is reabsorbed and creatinine is excreted. Ref: CURRENT Diagnosis & Treatmentchapter, Chapter 9; Advances in clinical chemistry, Volume 29 By Herbe E. Spiegel, Page 137; Nephrology in 30 Days By Robe F. Reilly, Mark A. Perazella, Page 234.', 'role': 'assistant'}]