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': 'Thyroid carcinoma - \nSelect and explain. \nA. Is often associated with hypothyroidism, B. Often produces hyperthyroidism, C. Is usually euthyroid, D. Occurs in toxic nodules', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]