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 of the following opioids is not given intrathecally? \nSelect and explain. \nA. Remifentanil, B. Morphine, C. Sufentanil, D. Fentanyl', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]