A pencil of light rays falls on a plane mirror and forms a real image, so the incident rays are:
$\left( A \right)$ Parallel
$\left( B \right)$ Diverging
$\left( C \right)$ Converging
$\left( D \right)$ Statement is false

Hint: Always a mirror will produce a virtual image of an object that is real whether it is a convex or a concave mirror. The focal length of a plane mirror is infinity. The parallel beam of ray projected on the plane mirror then there will be no deviation and the beam will get reflected. Apply this logic to determine whether the incident rays are parallel, diverging or converging.

Complete step by step answer:
The focal length of a plane mirror is infinity. The rays will get deflected and they will not have any images, if the parallel beam of light falls on the surface of the plane. Plane mirrors usually form virtual images. But we can arrange it in such a way that the plane mirror forms a real image. In a plane mirror always, a real object will produce virtual images and that is because the reflected rays diverge.
Light hitting the mirror reflects back at the same angle so that they are relative to each other. the rays will be unaffected because all of them shift the same amount. If a diverging ray hits a mirror then they will be diverging and a real image will not be formed. But if a converging ray hits a mirror then they will converge and form a real image.

Hence option $C$ is the correct option.

Note: If an object is virtual then that means object is at infinity. The focal length of a plane mirror is infinity. Always a mirror will produce a virtual image of an object that is real whether it is a convex or a concave mirror. In a plane mirror always, a real object will produce virtual images and that is because the reflected rays diverge. Plane mirrors usually form virtual images.