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
[{'content': 'Which one of the opioids has maximum plasma protein binding capacity ? \nSelect and explain. \nA. Morphine, B. Sufentanil, C. Fentanyl, D. Pethidine', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Sufentanil", 'role': 'assistant'}]