A driver sees a reduced, upright image of a following car in her rear-view mirror, which is a convex spherical mirror. Which of the following best explains why this image must be virtual?
a) Because the center of curvature of a convex mirror lies behind the reflective surface, any image it forms must also lie there, so the image is virtual.
b) Since images in a convex mirror are never inverted, and only non-inverted images are virtual, the image must be virtual.
c) Reflected rays from a convex mirror always diverge; their backward extensions intersect behind the mirror rather than the rays themselves, so the image is virtual.
d) The negative focal length of a convex mirror means it cannot focus light; therefore the reflected rays appear to meet only at the focal point behind the mirror, producing a virtual image.