This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Central Nervous system, Subject name: Pharmacology
Which of the following opioids has maximum plasma protein binding capacity? 
Select and explain. 
A. Morphine, B. Sufentanil, C. Fentanyl, D. Pethidine
B: Sufentanil
Answer: B: Sufentanil 
Explanation: Sufentanil has maximum plasma protein binding among opioids. Refer kDT 6/e