This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Opioids and Alcohols, Subject name: Pharmacology
Which of the following has most potent analgesic effect? 
Select and explain. 
A. Morphine, B. Fentanyl, C. Sufentanil, D. Meperidine
C: Sufentanil
Answer: C: Sufentanil 
Explanation: Sufentanil is most potent analgesic. It is 1000 times more potent than morphine. Fentanyl is 100 times more potent than morphine. Meperidine is less potent than Morphine but its analgesic efficacy is about same.