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
Not a feature of heroin (smack) withdrawal - 
Select and explain. 
A. Yawning, B. Muscle cramps, C. Hypersomnia, D. Hypertension
C: Hypersomnia
Answer: C: Hypersomnia 
Explanation: There is insomnia.