Which of the following improves the prognosis of pulp vitality after indirect pulp capping?
1. Use of calcium hydroxide.
2. Having a well sealed restoration.
3. Reducing other traumas to the pulp.
4. Removing all caries in the pulp cap area.

(1) (2) (3)

(4) only

(2) and (4)

(1) and (3)

All of the above.