This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bone Tumour, Subject name: Orthopaedics
[{'content': "Which of the following is a pulsatile tumor? \nSelect and explain. \nA. Osteosarcoma, B. Chondrosarcoma, C. Ewing's sarcoma, D. Osteoclastoma", 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'A Osteosarcoma Osteosarcoma>ABC>angioenfothelioma of bone>GCT Other bone tumors which can be pulsatile Angiosarcoma/ angioendothelioma of bone Aneurysmal bone cyst Metastasis from Renal cell carcinoma and Thyroid GYNAE & OBSTETRICS", 'role': 'assistant'}]