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': 'Allergic reactions in patients who receive amide-type local anesthetics for dental procedures are most likely caused by reaction of \nSelect and explain. \nA. Methylparaben, B. Contaminants, C. Lignocaine hydrochloride, D. Epinephrine', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]