This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Skeletal System, Subject name: Radiology
[{'content': 'Modality of choice for screening of bony metastases? \nSelect and explain. \nA. Plain radiograph, B. CT, C. MRI, D. Bone scan', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans DBone metastases can be seen at any site which maybe even far away from the primary as they spread by hematogenous route. So for their screening a modality which includes entire skeletal survey is employed - hence Bone scan is Best.', 'role': 'assistant'}]