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
[{'content': 'Not a feature of heroin (smack) withdrawal - \nSelect and explain. \nA. Yawning, B. Muscle cramps, C. Hypersomnia, D. Hypertension', 'role': 'user'}, {'content': 'Answer: C \nExplanation: There is insomnia.', 'role': 'assistant'}]