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': 'Allergic reactions occur with amino ester local anesthetics due to its metabolite: \nSelect and explain. \nA. P Aminobenzoic acid, B. Nitrosoamine, C. Both of the above, D. None of the above', 'role': 'user'}, {'content': "Answer: A \nExplanation: p-Aminobenzoic acid is one of the metabolites of ester-type compounds that can induce allergic-type reactions in a small percentage of patients. The aminoamides are not metabolized to p-aminobenzoic acid, and repos of allergic reactions to these agents are extremely rare. Ref: Miller's anesthesia-7th ed , Chapter 30.", 'role': 'assistant'}]