If a mirror is placed on the line MN, 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 triangle in the middle (with base at top side of square) facing downwards will now appear facing upwards, thus the second and last options will be eliminated.

Also, in the question figure at bottom right, the black colored triangle will appear at top right side, hence third option is the right image.

=> Ans - (C)