Why Are the Deep Sea Clays Mostly Red or Brown

Why are the deep sea clays mostly red or brown?

A) They are eroded mostly from desert areas and carried to the sea by winds or rainstorms.
B) They are mostly volcanic ash particles erupted onto the seafloor; this is their colour.
C) Slow settling of fine clay-sized mineral particles allows for complete oxidation of their iron by dissolved oxygen.
D) These are the residues of red algae blooms, dispersed by ocean currents to settle out everywhere.