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
[{'content': 'Which of the following is used to maintain abstinence in alcohol dependence? \nSelect and explain. \nA. Naltrexone, B. Clonidine, C. Disulfiram, D. Naloxone', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]