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': 'Drug of choice in MDP is: \nSelect and explain. \nA. Lithium, B. Amphetamine, C. Diazepam, D. Alprazolam', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Lithium', 'role': 'assistant'}]