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: Dental
[{'content': 'The CAD-CAM system uses \nSelect and explain. \nA. Cadmium in castings, B. A porcelain furnace with very high temperature, C. uses a video camera to all the prepared tooth, D. None of the above', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]