In the given mirror
C - centre of the sphere to which the mirror is part of
F - focus of the mirror
P - pole of mirror
A - point on mirror
D - point on principal axis.
If a ray of light starts from C and is incident on A from which point will the reflected ray pass through
C
'CA' will fall normal to the concave mirror. So by laws of reflection, the angle of incidence is 0 and so the angle of reflection will be 0. Hence the ray will retrace its path and pass through C (center of curvature).