All of the following provide resistance and retention for a short crown EXCEPT:

Features that IMPROVE retention and resistance for short crowns: Vertical grooves (add retention by creating mechanical undercuts — A provides retention). Proximal boxes (boxes on proximal walls increase resistance form — B provides resistance). Less occlusal convergence/more parallel walls (increases retention by reducing taper — D improves retention). A CHAMFER finish line (C) is a MARGIN DESIGN choice that affects esthetics and strength — it does NOT inherently provide retention or resistance form. The chamfer is chosen for ceramic margins, not for retention. C is the correct EXCEPT answer.