Crop plants should have high yields, including under stress, and a minimum of parts not needed for that yield. They should also have resistance to stresses which lower yield, such as drought and disease. Corn is a great example of this--it does C4 photosynthesis under drought stress and produces more grain per acre, by far, than other cereal grains in most settings.
Work Step by Step
Think about what a crop is about--yield--and what affects that (stresses, extraneous parts). The question is also dead wrong--we produce far more food now per person than 50 years ago, even with an increased population. The author of the question is pushing a political point of view, not science.