If a mirror is placed on the line AB, then which of the answer figures is the right image of the given figure ?

A horizontal mirror is placed, so the object on the top will appear at the bottom in reverse position and vice-versa.

So the pentagon in the middle facing upwards will now appear facing downwards, thus the first two options will be eliminated.

Also, in the question figure, the triangle is facing top left direction, hence it will face bottom left side in the mirror, hence fourth option is the right image.

=> Ans - (D)