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: Answer is c (Pre-renal failure) Plasmaurea / creatinine ratio of 20:1 is characteristic of prerenal ARF Rhabdomyolysis and chronic glomerulonephritis are causes of Intrinsic ARF and are associated with a plasma urea / creatinine ratio of < 10-15. Ureteric calculi are associated with post-renal ARF', 'role': 'assistant'}]