This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S., Subject name: Medicine
[{'content': 'True about DC shock treatment in AF: \nSelect and explain. \nA. Synchronized 50 Joules, B. Synchronized 250 Joules, C. Unsynchronized 50 Joules, D. Unsynchronized 250 Joules', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. A. Synchronized 50 Joulesa. In Atrial fibrillationb. Initial Monophasic = Synchronize DC shock of 50-100Joulesc. Initial Biphasic = 150J synchronized (upto 200) synchronized.', 'role': 'assistant'}]