This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Medicine
[{'content': 'The commonest cause of chronic renal failure is- \nSelect and explain. \nA. Diabetes mellitus, B. Hypeension, C. Pyelonephritis, D. Cystic disease of kidneys', 'role': 'user'}, {'content': "Answer: A \nExplanation: The most common cause of chronic renal failure is diabetes mellitus (20-40%)- high blood sugar levels caused by diabetes damage blood vessels in the kidneys (diabetic nephropathy). Hypeension(5-20 %)- damages blood vessels, cystic diseases of the kidney(5%), recurrent pyelonephritis, glomerular and tubulo-interstitial diseases, drugs etc. are other common causes of CKD. Reference : page 484 Davidson's Principles and practice of Medicine 22nd edition", 'role': 'assistant'}]