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 three vertical line at top left will now appear at bottom left, thus the first and last options will be eliminated.

Also, in the question figure at bottom right, only the vertical line in the middle is longer, hence they will appear at top left side, hence third option is the right image.

=> Ans - (C)