sunlight contains all the visible wavelengths of the electomagnetic spectrum. The spectrum of visible light to the human eye is 380nm to 780nm. All visible colors exist in this range. There is no certain number of colors. You must think of it more in terms of wavelengths. Whatever wavelength is reflected is the wavelength you see with your eye. But sunlight contains all visible light, therefore all visible wavelengths, and therefore all visible color.