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: Surgery
[{'content': 'Longest acting LA is ? \nSelect and explain. \nA. Bupivacaine+ Etidocaine, B. Bupivacaine + lignocaine, C. Procaine + lidocaine, D. Bupivacaine + mepivacaine', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Half life order - Bupivacaine> Etidocaine> Mepivacaine> Lignocaine.\nSame will be the order of duration of action.', 'role': 'assistant'}]