Answer: D. Darker, Lighter
Explanation: Think of a washcloth, notice how it becomes darker the more water it consumes? Colors have a similar effect. Adding a shade to a hue can greatly affect how “heavy” or dark a color may look.
A dull color is most likely desaturated and heavily tinted. A purer color will be a lot lighter and in most cases, saturated. We could consider “Baby blue” to be a pure color, and “Gray-blue” a dull color.