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': 'Speedball is cocaine mixed with: NEET 13 \nSelect and explain. \nA. Heroin, B. Cannabis, C. Amphetamine, D. LSD', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. Heroin', 'role': 'assistant'}]