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: Orthopaedics
[{'content': 'Three most common cancers metastasizing to bone -a) Kidneyb) Thyroidc) Breastd) Prostatee) Lung \nSelect and explain. \nA. abd, B. cde, C. bde, D. ade', 'role': 'user'}, {'content': "Answer: B \nExplanation: Certain tumors are known to be common sources of bone metastasis. The following primary tumors are the most common to metastasize in the bone; breast, prostate, lung, thyroid, kidney, and gastrointestinal tract.\nThe commonest source of metastatic bone disease is carcinoma of the breast. In males most common source is prostate carcinoma.\nBladder and uterine carcinomas are less common sources.\nIn children, skeletal metastases originate from neuroblastoma, Ewing's sarcoma, and osteosarcoma.", 'role': 'assistant'}]