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: Pathology
[{'content': 'A 70 year old male has a pathologic fracture of femur. The lesion appears lytic on X-ray with a circumscribed punched out appearance. The curetting from fracture site is most likely to show which of the following? \nSelect and explain. \nA. Diminished and thinned trabecular bone fragments secondary to osteopenia, B. Sheets of atypical plasma cells, C. Metastatic prostatic adenocarcinoma, D. Malignant cells forming osteoid bone', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Malignant cells forming osteoid bone', 'role': 'assistant'}]