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
In creating an access opening through a PFM crown made up of ceramic which of the following bur should be used: 
Select and explain. 
A. Carbide bur., B. Diamond bur., C. Both., D. None.
B: Diamond bur.
Answer: B: Diamond bur. 
Explanation: In creating an access opening through a PFM crown, diamond bur is used for ceramic, while carbide bur is used for metal.