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': 'In creating an access opening through a PFM crown made up of ceramic which of the following bur should be used: \nSelect and explain. \nA. Carbide bur., B. Diamond bur., C. Both., D. None.', 'role': 'user'}, {'content': 'Answer: B \nExplanation: In creating an access opening through a PFM crown, diamond bur is used for ceramic,\xa0while carbide bur is used for metal.', 'role': 'assistant'}]