After pulpotomy of a permanent central incisor in an 8 year old child, the most important clinical criterion/criteria of success is/are
1. completion of root formation.
2. internal resorption.
3. dentin bridge formation.
4. formation of pulp stones.

(2) and (4)

(1) and (3)

(1) (2) (3)

All of the above

(4) only