Violation

A preparation for a porcelain fused to metal crown with a porcelain butt joint margin should have a 1. 90 cavosurface margin. 2. subgingival finish line. 3. 1.2mm shoulder. 4. 90 axiogingival angle.

(1) and (3)

(1) (2) (3)

(2) and (4)

(4) only

All of the above.

Please describe the matter of abuse