A concave spherical mirror has radius of curvature of 30 cm. An object was placed 15 cm away of the pole in front of the mirror on the principal axis. Choose the correct option for the position, size and nature of the image formed, respectively.

A

At the focus, highly diminished point-sized, real and inverted

B

At infinity, highly enlarged, real and inverted

C

Behind the mirror, enlarged, virtual and erect

D

Between Focus and Centre, diminished, real and inverted