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: Unknown
At mu receptor, buprenorphine is - 
Select and explain. 
A. Partial agonist, B. Partial antagonist, C. Complete agonist, D. Complete antagonist
A: Partial agonist
Answer: A: Partial agonist 
Explanation: Ans. is 'a' i.e., Partial agonist .