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': 'What percent of giant cell tumor of bone are malignant ? \nSelect and explain. \nA. 5 - 10%, B. 15 - 20%, C. 25 - 30%, D. 50 - 60%', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]