Explanation:

- The given group of words is about formally ending something. It can be a system, practice, or institution.

- Option 1: Stop

- "Stop" means to bring something to a halt.

- It doesn’t imply a formal or complete ending.

- Option 2: Destroy

- "Destroy" means to ruin something completely.

- It often implies physical damage, not necessarily formal termination.

- Option 3: Kill

- "Kill" refers to ending life or existence, often in a literal sense.

- It's not suitable for formally ending systems or practices.

- Option 4: Abolish

- "Abolish" means formally ending a system or practice.

- It's typically used in legal or formal contexts.

- Option 4: Abolish is indeed the correct answer.