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 of the following opioids is not given intrathecally? 
Select and explain. 
A. Remifentanil, B. Morphine, C. Sufentanil, D. Fentanyl
A: Remifentanil
Answer: A: Remifentanil 
Explanation: None