The proposed experiment is trying to observe the color light (wavelength) that is best used by chlorophyll. This can be answered if we look at the chlorophyll function and plant color, as well as a bit of light theory. Chlorophylls absorb certain wavelengths better than others, this falls under the extremes of the light spectrum, this are blue colors (400-500nm wavelength) as well as red colors (600-700nm wavelength), meanwhile the colors in the middle there is less absorption, which is around green light, plants are green because chlorophyll reflects green light. Therefore taking this into consideration we can see that the correct answer is Green.