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
Which of the following opioid analgesic acts primarily through lc opioid receptors? 
Select and explain. 
A. Pentazocine, B. Methadone, C. Buprenorphine, D. Pethidine
A: Pentazocine
Answer: A: Pentazocine 
Explanation: None