This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Forensic Medicine
[{'content': 'Smack is \nSelect and explain. \nA. LSD, B. Cocaine, C. Cannabis, D. Heroin', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Smack is synthetic opioid Ref : Krishnan vij Textbook of Forensic medicine and Toxicology 5th edtion ; pg no - 492', 'role': 'assistant'}]