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
An addict presents with increased sweating, lacrimation, diarrhea, yawning and rhinorrhea. These symptoms may occur due to withdrawal of? 
Select and explain. 
A. Heroin, B. Cocaine, C. Cannabis, D. Alcohol
A: Heroin
Answer: A: Heroin 
Explanation: 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.