Microbes Capable of Growth on Corn Steep Liquor and Whey

Microbes capable of growth on corn steep liquor and whey are favored in industry, because the

A) media contain all necessary vitamins, which otherwise must be supplemented and are costly.
B) microbes do not produce toxins when grown on these media.
C) media are cheap waste products of other industrial processes.
D) media are not harmful to the environment.