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: Psychiatry
Most commonly abused opioid - 
Select and explain. 
A. Morphine, B. Diacetylmorphine, C. Oxycodine, D. Bupremorphine
B: Diacetylmorphine
Answer: B: Diacetylmorphine 
Explanation: Diacetylmorphine (heroin) is the most commonly abused opioid.