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': "In all of the following sympathectomy is effective except \nSelect and explain. \nA. Intermittent claudication, B. Hyperhydrosis, C. Raynaud's disease, D. Causalgia", 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]