Colors. I know this because of two main reasons. As you may have heard somewhere, someone may have been told to change the hue of a color by a little, which means to change the color a little bit. For example, the color yellow with its hue changed by a little bit could be orange.
The second reason is because I play Geometry Dash (an awesome game). It is a game where you jump over spikes and stuff by pressing left click. There is an option to create levels yourself, and changing the hue of colors is part of it.
Therefore, I know that your answer will be:
D) Colors