What material are you most likely to find in the D horizon

you're most likely to find Bedrock

The soil is comprised of various layers which are commonly known as the horizons, of which D is also a part of it. The D horizon is not always found. But it sometimes occurs below the B or the C horizon.

The materials that are present in this horizon are not affected by the weathering process. They are comprised of unaffected, raw mineral matter and are very hard and resistant like the parent rock. This layer gives rise to the formation of a much more complex layers that are comprised of numerous mineral matter.