The right answer is Wavelengths of energy.
White light is made up of all colors. The rainbow is actually the decomposition of white light by droplets of water like a prism.
Each color corresponds to an electromagnetic radiation of particular frequency and wavelength.
The sensitivity of the eye is maximum around 550 nm, in the yellow-green. The spectrum of visible light ranges from 400 to 780 nm but its perception depends on each individual (tastes and colors ...).