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 drug has more analgesic effects than morphine ? 
Select and explain. 
A. Heroin, B. Apomorphine, C. Codeine, D. Pethidine
A: Heroin
Answer: A: Heroin 
Explanation: None