The corn crop in an area is prone to infestation by larvae from moths that feed on the cornstalks and ears of corn. the techniques used by two farmers to protect the corn crop are described below.

technique a: sprayed his corn crop with an insecticide. the insecticide is known to kill all honeybee, butterfly, and moth larvae.
technique b: used a genetically modified variety of corn. the plant produces an insecticide which selectively kills only the moth larvae as it feeds on the corn.

which technique is likely to have less of an impact on the environment?

technique b because it may humans who consume corn to fight bacteria
technique a because it kills a broader variety of insects to protect the corn
technique b because it preserves the harmless insects and targets only the moth larvae
technique a because insecticide use is better for preserving the environment