ENEMY : FEUD :: RIVAL : QUARREL
Option: C
Explanation:
An analogy is a comparison in which a object or an idea is compared to another thing that totally differs from it.
Here, word rival means a contender or a competitor to be defeated. This more or less matches the word enemy than all the other given words.
In the same way, to feud is to quarrel (argument that goea on for a pretty long time) and this directly means the term quarrel.
The rest options do come into account as the meaning totally differs.
Answer choice A. So you have an Idea of what to look for and what you already know about the reading.
1. Unhealthy
2. Unfinished
3. Unable
4. Unhappy
5. Uncomplicated
6. Unfurnished
7. Unemployed
8. Unbelievable
9. Unclear
10. Uncomfortable
11. Unanswered
12. Unused
13. Unkind
14. Unafraid
15. Unacceptable
16. Unexpected