In taking a polysulfide impression for a cast restoration in the maxilla, the tray must
1. be rigid.
2. have occlusal stops.
3. cover the hard palate.
4. be coated with an adhesive cement.

(1) (2) (4)

(1) (2) (3)

(1) (3) (4)

(2) and (4)

All of the above