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': 'All are esters EXCEPT: \nSelect and explain. \nA. Prilocaine, B. Cocaine, C. Tetracaine, D. Chlorprocaine', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) PrilocaineRef: KDT 6th ed. / 352', 'role': 'assistant'}]