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

A vertical mirror is placed, so the object on the left will appear right in reverse position and vice-versa.

So the triangle (pointing downwards) at top left will still point downwards but will now be at top right, thus the first and last options will be eliminated.

Also, in the question figure, the pentagon that has a little black colour will have the colour but it will appear at left side, hence second option is the right image.

=> Ans - (B)