For composite resin preparations, cavosurface enamel margins are bevelled because
1. a bevelled margin produces a more favorable surface for etching.
2. a bevelled margin improves the edge strength of the composite resin.
3. after etching, the bonding agent reduces microleakage.
4. the procedure eliminates the need to polish the restoration

(1) and (3)

(1) (2) (3)

(2) and (4)

(4) only

All of the above