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: Surgery
[{'content': 'Which one of the opioid has maximum plasma protein binding capacity: \nSelect and explain. \nA. Morphine, B. Sufentanil, C. Fentanyl, D. Pethidine', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Protein binding capacity of opioids: Morphine: 30-40%., Pethidine: 70%, Fentanyl: 84%. Alfentanil: 92%., Sufentanil: 93%.', 'role': 'assistant'}]