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
The CAD-CAM system uses 
Select and explain. 
A. 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
C: uses a video camera to all the prepared tooth
Answer: C: uses a video camera to all the prepared tooth 
Explanation: None