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 in the middle will still face downwards, thus the second option will be eliminated.

Also, in the question figure, 'S' is at the left side of the triangle with a hollow circle, hence it will appear at right side with reverse image, hence third option is the right image.

=> Ans - (C)