GRE Logical Reading: ETS-GRE逻辑单题ETS - 8649TSE31M6CJWITJ$

Which of the following, if true, most calls into question the conclusion in the argument above? A. Though potatoes are an important staple crop in many parts of the world, people in most countries rely primarily on wheat or rice for sustenance. B. Potato farmers in many countries to which the new form of the fungus has spread cannot afford to increase their spending on fungicides. C. The new form of the fungus first began to spread when contaminated potato seeds were inadvertently exported from a major potato-exporting country. D. Potato farmers in most countries use several insecticides on their crops in addition to fungicides of the sort that kill the new form of the fungus. E. Most governments have funds set aside that can be used to alleviate the effects of large-scale disasters such as severe food shortages and floods.