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
Papillary necrosis is most commonly seen in-(AI 91) 
Select and explain. 
A. Diabetes Mellitus, B. Sickle cell anemia, C. Acute pyelonephritis, D. Analgesic nephropathy
D: Analgesic nephropathy
Answer: D: Analgesic nephropathy 
Explanation: Renal papillary necrosis is a disorder of the kidneys in which all or part of the renal papillae die. The renal papillae are the areas where the openings of the collecting ducts enter the kidney and where urine flows into the ureters.CausesRenal papillary necrosis often occurs with analgesic nephropathy. This is damage to one or both kidneys caused by overexposure to pain medicines. But, other conditions can also cause renal papillary necrosis, including:Diabetic nephropathyKidney infection (pyelonephritis)Kidney transplant rejectionSickle cell anemia, a common cause of renal papillary necrosis in childrenUrinary tract blockage This is a list of causes in order of incidence.A: analgesic abuse (phenacetin, NSAID's, paracetamol: especially in combination)D: diabetes mellitusS: sickle cell diseaseP: pyelonephritis (especially in children)O: obstructionR: renal vein thrombosisT: renal tuberculosis (not usually confined to papillae)C: cirrhosis