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

When a mirror is placed on the line MN,

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

The triangle which is towards top will be towards bottom in the mirror image.

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

Hence, the correct answer is Option B