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': 'Internal appearance of the lesion can be determined by the term: \nSelect and explain. \nA. Discoid, B. Circular, C. Pedunculated, D. Mixed density', 'role': 'user'}, {'content': 'Answer: D \nExplanation: The internal appearance of a lesion can be classified into one of three basic categories:\n\nTotally radiolucent\nTotally radiopaque\nMixed radiolucent and radiopaque (mixed density).\n\nA totally radiolucent interior is common in cysts, and a totally radiopaque interior is observed in osteomas. The mixed density internal structure is seen as the presence of calcified structures (white) against a radiolucent (black) backdrop.\nOral radiology White & Pharaoh 7th edition: page no 277', 'role': 'assistant'}]