This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Adverse Drug Effect, Subject name: Pharmacology
[{'content': 'Renal papillary necrosis is caused by? \nSelect and explain. \nA. NSAID, B. Cocaine, C. Heroin, D. Morphine', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) NSAIDRef Harrisonys Internal Medicine 18/e, Table 285-3, Radiology Illustrated, Uroladiology: Uroradiology by SeungHyup Ki 2/e, p 471', 'role': 'assistant'}]