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': 'The drug used in the treatment of cessation of smoking  & tobacco addiction \nSelect and explain. \nA. Vareniciline, B. Acamprosate, C. Baclofen, D. Naltrexone', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Vareniciline is a partial agonist at\xa0α4\xa0β2 subtype of Nicotine receptor used to treat tobbacco addiction.', 'role': 'assistant'}]