What unit of measurement identifies the lightness or darkness of a color, or the saturation, density, or concentration of color?

• A. Hue
• B. Level
• C. Tone
• D. Saturation

Answer: (B)

Tone describes how light or dark a color is and also how saturated (vivid) or dull it appears. It sits on a light–dark scale and changes as you adjust brightness or add gray, which reduces saturation. Hue is the color family (red, blue, etc.), saturation refers specifically to the color’s intensity, and Level isn’t a standard term used for color properties here. So tone is the best fit because it links both lightness/darkness and the sense of saturation in a single attribute.