Which of the Following Describes a Characteristic Process in the Formation

Which of the following describes a characteristic process in the formation of a pedalfer soil?

A) Humus accumulates below the solum in the C horizon.
B) Soil bacteria produce organic acids that precipitate calcium carbonate in the B horizon.
C) Clays are eluviated upward from the C horizon.
D) Iron oxides and aluminum- rich clays are precipitated in the B horizon.