单选题 Cotton farmers in Central America began to use pesticides
A．because of an intensive government advertising campaign.
B．in response to the appearance of new varieties of pest.
C．as a result of changes in the seasons and the climate.
D．to ensure more cotton was harvested from each crop.

【正确答案】 D

【答案解析】[解析] 通过cotton farmers in Central America定位到第四段，第一句看不懂没关系，第一句里边也没有与答案相关的元素。往下看farmers都做了什么，下一句最后出现了the farmers avidly took to pesticides as a sure measure to boost crop yield，即农场主要确保收成，D项符合这个意思。
[干扰项] A项和C项都是无中生有；B项在读不懂的情况下容易被误选，正是因为农民为了丰收大量使用农药才导致了害虫变异出抗药性的新品种，而不是在最初就要用农药反击新害虫。