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
The drug for OPD analgesia is - 
Select and explain. 
A. Morphine, B. Pethidine, C. Fentanyl, D. Alfentanil
D: Alfentanil
Answer: D: Alfentanil 
Explanation: Ans. is 'd' i.e., Alfentanil Drugs useful for day care surgery o Propofol o Sevoflurane, desflurane & isoflurane o Midazolam o Mivacurium o Alfantanil