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
Heroin, an addict drug contains 
Select and explain. 
A. ASA, B. Acetyl morphine, C. Pentazocine, D. Propoxyphene
B: Acetyl morphine
Answer: B: Acetyl morphine 
Explanation: None