This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Radiology
[{'content': 'What is seen in the X-ray of femur below \nSelect and explain. \nA. Sunburst calcification, B. Onion peel effect, C. Codmann triangle, D. Bone marrow invasion', 'role': 'user'}, {'content': 'Answer: C \nExplanation: .', 'role': 'assistant'}]