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 one of the opioids has maximum plasma protein binding capacity ? 
Select and explain. 
A. Morphine, B. Sufentanil, C. Fentanyl, D. Pethidine
B: Sufentanil
Answer: B: Sufentanil 
Explanation: Ans. is 'b' i.e., Sufentanil