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
On the mammogram, all of the following are the features of a malignant tumor except: 
Select and explain. 
A. Speculation, B. Microcalcification, C. Macrocalcification, D. Irregular mass
C: Macrocalcification
Answer: C: Macrocalcification 
Explanation: None