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
[{'content': "Polka dot sign on CT is a feature of \nSelect and explain. \nA. Vertebral hemangioma, B. Eosinophilic granuloma, C. Osteosarcoma, D. Ewing's sarcoma", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Polka dot sign/ Corduroy/vertical striations –\xa0Vertebral hemangioma.', 'role': 'assistant'}]