Which statement about soil color is true? select one: a. soils vary in color based on their depth. b. soils do not vary in color based on their depth. c. soils close to earth's surface are always darker. d. soils far from earth's surface are always darker.

The answer is b. Soils do not vary in color based on their depth.
Soil color is affected by the nutrient/Organic matter that it contains rather than its Depth.
For example, dark and brown soil indicates high percentage of organic matters contained while yellow and red soil indicates high concentration of Iron.