This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Drug Abuse, Subject name: Forensic Medicine
[{'content': 'Cotton fever is due to the abuse of: \nSelect and explain. \nA. Amphetamine, B. Heroin, C. Phencylidine, D. Cocaine', 'role': 'user'}, {'content': 'Answer: B \nExplanation: COTTON FEVER : Fever developing due to injection of a water extract of the cotton remaining after the heroin supply is used in a "bag"', 'role': 'assistant'}]