This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Toxicology - 1, Subject name: Forensic Medicine
[{'content': 'Heroin is? \nSelect and explain. \nA. Cocaine, B. Opioid, C. Dhatura, D. Cannabis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Heroin is diacetyl morphine (semisynthetic form of opium) Classification of opiods: (1) Natural: morphine, codeine.(2) Semi-synthetic: heroin, hydromorphone, oxymorphone, oxycodone. (3) Synthetic: meperidine, methadone, paregoric, diphenoxylate, fentanyl, propoxyphene,levarphanol tarate.', 'role': 'assistant'}]