Which of the following is the correct mirror image of the word KATAK?

The correct answer is Option (3) → 

In a mirror image the order of the letters is reversed and each letter is turned left to right. A letter with a vertical line of symmetry (A, T) looks the same in the mirror; K does not, so both K's turn round.

Tip: KATAK reads the same both ways, so the reversed order alone changes nothing; only the turned K's tell the mirror image apart from the word itself (Option (2)).