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': 'Which of the following is not a content of plane LA \nSelect and explain. \nA. Methyl paraben, B. Epinephrine, C. Nacl, D. Lignocaine', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]