Prep 93 拜托拜托为什么是A 不是E? 谢谢谢谢

Following several years of declining advertising sales, the Greenville Times reorganized its advertising sales force two years ago.Before the reorganization, the sales force was organized geographically, with some sales representatives concentrating on city-center businesses and others concentrating on different outlying regions.The reorganization attempted to increase the sales representatives’ knowledge of clients’ businesses by having each sales representative deal with only one type of industry or of retailing.After the reorganization, advertising sales increased.

In assessing whether the improvement in advertising sales can properly be attributed to the reorganization, it would be helpful to find out each of the following EXCEPT:

原文：因为advertising sales下降，所以重新组织。原来的组织是按地域划分，重新组织后以增加行业知识主，导致advertising sales增加。
题目：以下哪个选项可以评估advertising sales的增加是因为重新组织。

A. Two years ago, what proportion of the Greenville Times’s total revenue was generated by advertising sales?
两年前，advertising sales产生了多少利润，这个好像无关吧。
B. Has the circulation of the Greenville Times increased substantially in the last two years?
两年前，流量增加。也无关。
C. Has there been a substantial turnover in personnel in the advertising sales force over the last two years?
人员调整？也无关。
D. Before the reorganization, had sales representatives found it difficult to keep up with relevant developments in all the types of businesses to which they were assigned?
重新组织之前，销售代表是否发现很难跟上他们工作方面的发展。
E. Has the economy in Greenville and the surrounding regions been growing rapidly over the last two years?
是否周边地区和G的经济发展很快？

我觉得选D。组织前的知识匮乏到组织后的提高知识水平作为比较。说明了正是因为只是不够导致的。
请指教。