________,________,And ________ Are Among the Combination of Factors That the Great

________,________,and ________ are among the combination of factors that The Great Lakes - Corn Belt region's agricultural productivity is some of the best in the world.

A) Fertile soils,excellent transportation,mild winters
B) Technology,favorable government policy,work ethic
C) Experienced farmers,cash-grain farms,subsidized farming
D) Adequate water availability,mixed farming,use of high yield crops