The Corn Blight of 1970 Was Brought Under Control By

The corn blight of 1970 was brought under control by:

A) crossing highly uniform U.S. corn varieties with genetically diverse ancestral varieties from Mexico.
B) strange weather patterns resulting in a drought that killed the fungus.
C) the accidental release of a genetically engineered fungus from a research lab.
D) repetitive treatment with various chemical sprays.
E) pollution that seemed to have a greater adverse effect on the corn blight fungus than on the corn itself.