Plant scientists have been able to genetically engineer vegetable seeds to produce crops that are highly resistant to insect damage. Although these seeds currently cost more than conventional seeds, their cost is likely to decline. Moreover, farmers planting them can use far less pesticide, and most consumers prefer vegetables grown with less pesticide. Therefore, for crops for which these seeds can be developed, their use is likely to become to norm.
Which of the following would be most useful to know in evaluating the argument above?
A. Whether plant scientists have developed inset-resistant seeds for every crop that is currently grown commercially
B. Whether farmers typically use agricultural pesticides in larger amounts than is necessary to prevent crop damage
C. Whether plants grown form the new genetically engineered seeds can be kept completely free of insect damage
D. Whether seeds genetically engineered to produce insect-resistant crops generate significantly lower per acre crop yields than do currently used seeds
E. Whether most varieties of crops currently grown commercially have greater natural resistance to insect damage than did similar varieties in the past
我觉得D最重要，可答案是B | 
