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: Pathology
Which is the most common cause of papillary necrosis 
Select and explain. 
A. Analgesics abuse, B. Chronic alcoholism, C. Acute pyelonephritis, D. Diabetes mellitus
D: Diabetes mellitus
Answer: D: Diabetes mellitus 
Explanation: Though all the options are causes of renal papillary necrosis, most common cause is Diabetes mellitus.