Why Do the Sand Dunes in the West Vary from Those

Multiple Choice

Why do the sand dunes in the west vary from those in the east in the figure below?

A) The average size of the sand clasts differs in the two areas.
B) There is slightly more rain to the east.
C) The material to the east is closer to an igneous-rock source area, from which the dune sediment is significantly derived.
D) The winds are predominantly in one direction in the west but blow more complexly in the east.