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': 'Most common cause of Vertebra plana \nSelect and explain. \nA. Eosinophilic granuloma, B. Leukemia, C. TB, D. Metastasis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Vertebra plana:\n\nUniform collapse of a vertebral body into a thin, flat disc.\nM/c cause - Eosinophilic granuloma.', 'role': 'assistant'}]