An important characteristics of the B-horizon in tropical ferruginous soils is t...

The question is asking about an important characteristic of the B-horizon in tropical ferruginous soils. The B-horizon is a layer of soil that is found below the A-horizon, which is the topmost layer of soil.

The B-horizon is known for its accumulation of oxides. Oxides are compounds that contain oxygen and another element, such as iron oxide or aluminum oxide. In tropical ferruginous soils, which are found in areas with high rainfall and high temperatures, the B-horizon tends to have a high concentration of these oxides.

The accumulation of oxides in the B-horizon is important because it can affect the fertility and nutrient content of the soil. These oxides can bind with nutrients, making them less available to plants. They can also affect the soil's ability to retain water, which is important for plant growth.

Therefore, the correct answer is Option C: accumulation of oxides. This is an important characteristic of the B-horizon in tropical ferruginous soils.