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: Medicine
[{'content': 'A-48 year old presents with history of precordial chest pain. He has BP of 80/60 mm of Hg. EKG shows wide QRS complex with no preceding P waves and a rate of 112/min. The most immediate step in the management of this patient would be \nSelect and explain. \nA. Intravenous lignocaine, B. DC electrical cardioversion, C. Overdrive atrial pacing, D. Primary percutaneous transluminal angioplasty', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]