This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology and breast, Subject name: Surgery
[{'content': 'Percentage of cold nodules that becomes malignant are \nSelect and explain. \nA. 5%, B. 15%, C. 20%, D. 40%', 'role': 'user'}, {'content': "Answer: C \nExplanation: 20% of 'cold' swellings and some 5% functioning or 'warm' swellings will be malignant.Ref: Bailey and Love, page no: 804", 'role': 'assistant'}]