The correct option is A revive
The word 'abolish' refers to formally putting an end to a practice or institution.
Option A, eradicate refers to destroying something completely.
Option B, end refers to a goal or desired result.
Option C, revive refers to restoring to life and consciousness.
Option D, encourage refers to giving hope, confidence or courage to someone.
Thus, according to the meaning, the word 'revive' is the opposite of the word 'abolish'.