This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Toxicology - 3, Subject name: Forensic Medicine
[{'content': 'Most common abused substance is: \nSelect and explain. \nA. Datura, B. Marijuana, C. Cocaine, D. Heroin', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Cannabis / marijuana:Most commonly abused substance in India Opium: Derived from Papaver somniferum; poison of choice for suicide Heroin / brown sugar: Synthetic derivative of opium Datura: Roadside poison or railway poison Cocaine: Obtained from dried leaves of Erythroxylum coca', 'role': 'assistant'}]