41. Which of the following practices is consistent with the production of organic crops according to the United States Department of Agriculture? (A) Using sodium nitrate as a fertilizer on green, leafy vegetables
(B) Using strychnine to prevent buildup of aphid populations in field crops
(C) Using chemicals known as pheromones to disrupt insect mating cycles
(D) Using sewage sludge to improve the fertility and structure of soil
(E) Using genetically modified plant varieties that kill insects that chew their leaves