One of the challenges facing the world today is supplying enough food for the human population. Farming with genetically modified plants is a possible solution to this challenge. What is a concern with using GM plants? A. Farming with GM plants that are resistant to chemical herbicides may lead to overuse of weed-killing compounds. B. Farming with GM plants requires less land and energy, which may lead to lower food costs and an economic crisis for farmers. C. GM plants require more insecticide use, which may increase the chance of chemical residues in the food supply. D. Scientific studies on GM plants are not available so the effects of GM plants are unknown.