This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Central Nervous system, Subject name: Pharmacology
[{'content': '"Opioids" differ from "opiates" in that they are: \nSelect and explain. \nA. More powerful in action, B. More long acting, C. Synthetic derivatives, D. Derived directly from opium', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Opiods are synthetics while opiates are semi synthetic. Opiods include pethidine,fentanyl,methadone,dextropropoxyphene,tramadol. Semisynthetic opiates include heroin ,pholcodine,ethylmorphine . Ref: KD Tripathi 8th ed.', 'role': 'assistant'}]