This assignment will have you prove that you understand how to simplify a photograph using color as your primary element.
You can choose to use any type of color simplification process but the point is to limit the array of colors which make it into your photograph. You can choose to shoot a color highlight photograph, a monochromatic photograph or a photograph which uses just analogous colors or complimentary colors.
The point is that you just don't point and click at any colors you wish. See colors in your world and know how to separate them to create a visually appealing photograph.