In determining the ideal proximal outline form for a Class II amalgam cavity preparation in a molar the
1. axial wall should be 1.5mm deep.
2. gingival cavosurface margin must clear contact with the adjacent tooth.
3. proximal walls diverge occlusally.
4. facial and lingual proximal cavosurface margins must just clear contact with the adjacent tooth.

(2) and (4)

(1) (2) (3)

(1) and (3)

All of the above.

(4) only