The Herbicide Roundup Kills Weeds

The herbicide Roundup kills weeds. Why do farmers want crops which are genetically engineered to be "Roundup Ready?"

A) Those crops can produce their own weed killer, preventing weeds from growing around them.
B) Those crops resist the Roundup that then kills all the weeds around them when it's sprayed.
C) Those crops are less expensive to grow because farmers don't need to apply an herbicide to them to keep the weeds down.
D) Those crops grow faster when the herbicide Roundup is sprayed on them.
E) Farmers don't really want those crops, but if they use Roundup as an herbicide the chemical company that makes it requires the use of the genetically engineered crops.