Whatever be the position of the object, the image formed by a mirror is virtual, erect and smaller than the object. The mirror then must be:(a) plane (b) concave (c) convex (d) either concave or convex

(c) convex

Explanation

A convex mirror is a mirror that is curved outward in the middle. It is also known as diverging mirrors, due to the fact that when parallel incident rays fall on the surface of the mirror, the rays get diverge, and give a wider field of view.

It always forms virtual, erect, and diminished images irrespective of the distance between the object and the mirror.