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
Allergic reactions occur with amino ester local anesthetics due to its metabolite: 
Select and explain. 
A. P Aminobenzoic acid, B. Nitrosoamine, C. Both of the above, D. None of the above
A: P Aminobenzoic acid
Answer: A: P Aminobenzoic acid 
Explanation: 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.