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': 'Treatment of choice for medullary carcinoma: \nSelect and explain. \nA. Thyroxin therapy., B. Radioiodine., C. External radiation, D. Total Thyroidectomy.', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]