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: Radiology
Hallmark of breast malignancy on mammography : 
Select and explain. 
A. Low density lesion, B. Smooth margin, C. Clusters of micro calcification, D. Popcorn calcification
C: Clusters of micro calcification
Answer: C: Clusters of micro calcification 
Explanation: Microcalcification's is pathognomonic sign for breast carcinoma. It may be seen in 30% cases of invasive carcinoma and 95% of cases of DCIS (granular and casting).