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: Anaesthesia
[{'content': 'Most cardiotoxic local anesthetic ? \nSelect and explain. \nA. Procaine, B. Bupivacaine, C. Cocaine, D. Lidocaine', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Bupivacaine", 'role': 'assistant'}]