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
CEREC AC which is true 
Select and explain. 
A. Creates the image by video recording, B. Laser beam is used, C. LED is used, D. Composite metal resin alloy etc
C: LED is used
Answer: C: LED is used 
Explanation: None