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': 'Risk of malignancy in cold nodule of thyroid is \nSelect and explain. \nA. 0.10%, B. 2%, C. 20%, D. 30%', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Risk of malignancy in hot nodule is 4%.\nRisk of malignancy in cold nodule is 20%.', 'role': 'assistant'}]