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': 'DOC for "rapid cyclers" type of bipolar disorder is- \nSelect and explain. \nA. Carbamazepine, B. Valproate, C. Phenytoin, D. Lithium', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]