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: Pharmacology
[{'content': 'Buprenorphine paial agonist at which opioid receptor? \nSelect and explain. \nA. Mu, B. Kappa, C. Delta, D. Lambda', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Buprenorphine is paial agonist on mu receptor and antagonist at Kappa receptor. REF : katzung pharmacology : 14th ed', 'role': 'assistant'}]