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 young patient sustains cardiac arrest, in the medical ward. Immediate defibrillation is advised when the ECG shows: \nSelect and explain. \nA. Ventricular Tachycardia, B. Asystole, C. Electromechanical dissociation, D. Persistant Bradyarrhythmia', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Answer is A (Ventricular Tachycardia) Defibrillation is indicated when cardiac arrest occurs secondary to ventricular fibrillation or pulseless ventricular tachycardia (shockable rhythms)', 'role': 'assistant'}]