This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Mood Disorders, Subject name: Psychiatry
[{'content': 'Which of the following indications of deep brain stimulation is not FDA approved? \nSelect and explain. \nA. OCD, B. Major depression, C. Parkinsonism, D. Dystonia', 'role': 'user'}, {'content': "Answer: B \nExplanation: FDA approved indications for deep brain stimulation are: a. Parkinson's disease and essential tremors b. Dystonia c. Obsessive compulsive disorder", 'role': 'assistant'}]