Brown color of soil due to?

Explanation

The brown color of soil is primarily due to the presence of organic matter and minerals, particularly manganese dioxide. Here's an explanation of the correct option (d) Organic matter and manganese dioxide: Organic Matter: Humus is the dark, organic component of soil formed by the decomposition of plant and animal residues. It contributes to the brown color of soil. Manganese Dioxide: Manganese dioxide is a mineral that can impart a brown color to soil. It often occurs in soils and, depending on its concentration, can influence the soil's color.