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
Percentage of cold nodules that become malignant are 
Select and explain. 
A. 10%, B. 15%, C. 20%, D. 40%
C: 20%
Answer: C: 20% 
Explanation: About 80% of discrete swellings are cold. The risk of malignancy is higher in "cold" lesions (20%) compared to "hot" or "warm" lesions (<5%) Ref: Bailey and love 27th edition Pgno :804