A spherical mirror forms an image of magnification -1. This means the image is:
Correct: C
Magnification (m) is given by -v/u for mirrors. A negative sign for magnification indicates that the image is real and inverted. A magnitude of 1 (|m|=1) means the image is of the same size as the object. Thus, m = -1 implies a real, inverted, and same-size image. This specific case occurs when an object is placed at the center of curvature (C) of a concave mirror.