This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Central Nervous system, Subject name: Pharmacology
[{'content': 'An addict presents with increased sweating, lacrimation, diarrhea, yawning and rhinorrhea. These symptoms may occur due to withdrawal of? \nSelect and explain. \nA. Heroin, B. Cocaine, C. Cannabis, D. Alcohol', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Heroin is a semi synthetic derivative of opium. Withdrawal symptoms are lacrimation, sweating, yawning,anxiety,restlessness, rhinorrhoea and tremors seen 8-12 hours after last dose. All the other drugs donot have the above set of side effects. Ref: KD Tripathi 8th ed.', 'role': 'assistant'}]