This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General Surgery, Subject name: Surgery
[{'content': 'On mammogram all of the following are the features of a malignant tumor except: \nSelect and explain. \nA. Spiculation, B. Microcalcification, C. Macrocalcification, D. Irregular mass', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Benign Malignant Opacity Smooth margin Low density Homogeneous Thin halo Ill definedQ margin Irregular stellate, spiculatedQ margin, comet tailQ High densityQ Heterogeneous Wide haloQ Calcification MacrocalcificationQ (>0.5 mm in diameter) MicrocalcificationQ (<0.5 mm in diameter)', 'role': 'assistant'}]