In my opinion, the answer is B. horizons because they are commonly referred to as the subsoil. They are a zone of accumulation where rainwater percolating through the soil has leached material from above and it has precipitated within the horizons or the material may have weathered in place. Well, drained soils typically have the brightest color development within the horizons. I hope that this is the answer that you were looking for and it has helped you.
