To differentiate colors in the retina present in the human eye, there are

To differentiate colors in the retina, present in the human eye, there are (a) Cones. Cones are specialized photoreceptor cells located in the retina that enable color vision. These cells are sensitive to different wavelengths of light, allowing the perception of various colors.
Cones are concentrated mainly in the central region of the retina called the fovea, which is responsible for high-resolution vision. There are three types of cones, each sensitive to different wavelengths of light: red, green, and blue. By comparing the signals from these cones, the brain can discern a wide range of colors.
In contrast, (b) Rods, another type of photoreceptor in the retina, are responsible for low-light vision and do not contribute significantly to color perception. The (c) Cornea is the transparent outer layer of the eye, and the (d) Choroid is a vascular layer that provides blood supply to the retina but does not directly contribute to color vision.