Theories of the Evolution of Glaciers Include,as Possible Causes,all of the Following

Multiple Choice

Theories of the evolution of glaciers include,as possible causes,all of the following EXCEPT

A) periods of excessive dust in the atmosphere.
B) changes in the shape,the tilt,and the seasonal positions of the earth's orbit around the sun.
C) the drifting of continental plates over tropical regions.
D) the periodic changes in the amount of solar energy received on the earth's surface.