The question is Which color of light has the greatest frequency?
the answer is Violet.
White light is a combination of all colors of in the color spectrum, that is it has all the colors of the rainbow. Combining primary colors of light like red, blue, and green creates secondary colors such as yellow, violet among others. One end of the spectrum is red light, with the longest wavelength and lowest frequency, while on the other end there is violet color with the shortest wavelength and the greatest frequency.