One Advantage of Using an Enormous Mirror to Collect Light

One advantage of using an enormous mirror to collect light in a telescope is that the real image is relatively bright. But there is also a benefit to letting the waves of starlight pass through the largest possible apertures. Sending a light wave through a small aperture truncates the wave severely and causes it to diffract. Because of this diffraction, light from a white star

A) forms a small rainbow of light in the real image.
B) forms a single spot of light in the real image, but not quite at the appropriate location.
C) forms a single spot of yellowish light in the real image.
D) spreads outward to form a fuzzy spot in the real image.