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': 'A 45 yrs male presented with an expansile lesion in the centre of femoral metaphysis. The lesion shows endosteal scalloping & punctuate calcifications.Most likely diagnosis is - \nSelect and explain. \nA. Osteosarcoma, B. Chondrosarcoma, C. Simple bone cyst, D. Fibrous Dysplasia', 'role': 'user'}, {'content': 'Answer: B \nExplanation: You can simply solve this question by knowing very simple fact that punctate calcification is seen in cartilaginous tumors and amongst the given options, only chondrosarcoma is cartilaginous.', 'role': 'assistant'}]