Which horizon in a typical soil profile is characterised by the accumulation of materials leached from the overlying layers?

The B horizon, also called the subsoil or zone of illuviation, is where materials such as clay, iron oxides, and humus leached from the A horizon accumulate. The A horizon is the zone of eluviation (loss), while the C horizon consists of weathered parent material. The O horizon contains organic matter at the surface.