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: Pathology
Causes of papillary necrosis in kidney are/is: 
Select and explain. 
A. Diabetes mellitus, B. Sickle cell disease, C. Analgesic abuse, D. All
D: All
Answer: D: All 
Explanation: Ans. d (All). (Ref. Robbin's, Pathology, 6th/pg.924)CAUSES OF PAPILLARY NECROSIS (mnemonic--POSTCARD):# Pyelonephritis# Obstructive uropathy# Sickle cell disease# TB and trauma, tubular necrosis, transplant rejection# Cirrhosis (alcoholism, coagulopathy)# Analgesics# Renal vein thrombosis# Diabetes, Dehydration