Final answer:
The three colors that are distinguished by the cones in the retina include all of the following except gray.
Step-by-step explanation:
The three colors that are distinguished by the cones in the retina include all of the following except gray (option C).
Cones are photoreceptor cells in the retina of the eye that are responsible for color vision. There are three types of cones that are maximally sensitive to different ranges of wavelengths, and they are responsible for our ability to perceive colors. The three colors that are distinguished by cones are green, red, and blue.