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
Chamfer finish line is usually indicated in cases of: 
Select and explain. 
A. All metal restorations, B. All ceramic restorations, C. Facial margin of PFM crown, D. All of the above
A: All metal restorations
Answer: A: All metal restorations 
Explanation: Chamfer

It is an obtuse-angled finish line.
It is distinct.
Exhibits least stress.
Most conservative.
Indicated where metal forms the margin of a restoration, e.g. complete metal crown. Should not be given for porcelain restorations as the obtuse angle produces shearing forces which is not well tolerated by porcelain.
It is prepared using a round-end tapering diamond. This is produced by sinking in half the diamond into the tooth. The tip produces the chamfer while the sides give the necessary taper to the axial surface.