This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous (Local and Regional Anesthesia), Subject name: Anaesthesia
[{'content': 'Most cardiotoxic local anaesthetic: \nSelect and explain. \nA. Dibucaine, B. Bupivacaine, C. Lignocaine, D. Chlorprocaine', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans: (b) BupivacaineRef: KDT 6th ed. 1357* Bupivacaine is a local anesthetic agent from Amide group.* It is most cardiotoxic LA.* Shortest acting LA: Chlorprocaine* Longest acting LA: Dibucaine* Most commonly used LA: Lignocaine* Local anesthetic which causes methhemoglobinemia: Prilocaine', 'role': 'assistant'}]