This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anaesthesia, Subject name: Pharmacology
[{'content': 'Naturally occurring local anesthetic:(1997) \nSelect and explain. \nA. Cocaine, B. Procaine, C. Lignocaine, D. Bupivacaine', 'role': 'user'}, {'content': 'Answer: A \nExplanation: aRef: KDT, 5th ed, p. 324 & 4th ed, p. 165', 'role': 'assistant'}]