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: 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: None