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': 'Which of the following cannot been seen radiographically? \nSelect and explain. \nA. Interproximal caries, B. Root caries, C. Deep caries, D. None of the above', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]