This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
[{'content': 'All of the following are true about opioids except ? \nSelect and explain. \nA. Naloxone is short acting, B. Naltrexone is used to lower craving in alcoholics, C. Nalmefene can be used for opioid poisoning, D. Nalmefene is shorter acting than naloxone', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]