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': 'Gate control theory was proposed by \nSelect and explain. \nA. Lofgren, B. Melzack and Wall, C. Alexander Beunet, D. William Halsted', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]