This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Electrocardiography, Subject name: Medicine
[{'content': 'A patient after myocardial infarction becomes pulse- less and BP crashes. Diagnosis is? \nSelect and explain. \nA. Monomorphic ventricular tachycardia, B. Bidirectional tachycardia, C. Polymorphic ventricular tachycardia, D. Ventricular fibrillation', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) Monomorphic ventricular tachycardia.', 'role': 'assistant'}]