If a mirror is placed on line PQ in the question figure, then which of the answer figures is the correct mirror image of the question figure?

When a mirror is placed on the line PQ,

The facing of the figure to the left and right direction changes to the opposite direction in the mirror image(left facing changes to right and vice versa). There won't be change in top and bottom direction.

The triangle on the left with greater height will be on the right in the mirror image.

The triangle on the right with lesser height will be on the left in the mirror image.

$$\therefore\ $$The mirror image of the given figure is

Hence, the correct answer is Option D