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
DOC for rapid cycling MDP - 
Select and explain. 
A. Lithium, B. Valproate, C. Calcium channel blocker, D. Carbamazepine
B: Valproate
Answer: B: Valproate 
Explanation: DOC for rapid cyclers is Valproate. 
Alternatives are Lithium, Carbamazepine and Lamotrigine.