If a polyvinyl siloxane material is used to make the final impression for a maxillary cast restoration, the impression tray must
1. be rigid.
2. have occlusal stops.
3. be coated with an appropriate adhesive.
4. cover the hard palate

(1) (2) (3)

(1) and (3)

(2) and (4)

(4) only

All of the above.