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
Which of the following liver mets appear hypoechoic on USG? 
Select and explain. 
A. Ca. Colon, B. Ca. Breast, C. Ca. Bladder, D. Mucinous adenocarcinoma
B: Ca. Breast
Answer: B: Ca. Breast 
Explanation: Hypoechoic lesions can be secondary to lymphoma, melanoma, breast and lung carcinoma, and less commonly, related to gastrointestinal malignant tumors. Ref: Liver Malignancies: Diagnostic and Interventional Radiology By Carlo Baolozzi, Riccardo Lencioni, 1999, Page 180