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
Drug of choice for MDP is: 
Select and explain. 
A. Lithium, B. Diazepam, C. Olanzapine, D. Carbamazepine
A: Lithium
Answer: A: Lithium 
Explanation: None