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': 'One of the followig opioid derivatives is a paial agonist as well as antagonist- \nSelect and explain. \nA. Buprenorphine, B. Naloxone, C. Nalorphine, D. Naltrexone', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., Nalorphine", 'role': 'assistant'}]