Explanation :
Mirrors are made up of silver coated glass. The mirrors used to focus an image at a point. It can be of any type like a plane mirror, concave mirror and the convex mirror.
Mirrors follow the law of reflection. The law states that :
A lens is used to refract light. The amount of refraction depends on the type of material and its shape. It can be of two types i.e. convex and concave lens.
So, the correct option is (B) "Mirrors form images by reflecting light; lenses do not".