Following several years of declining advertising sales, the Greenvile Times reorganized its advertising sales force. Before 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’ business by having each sales representative deal with only one type of industry or of retailing. After the reorganization, revenue from advertising sales increased.

In assessing whether the improvement in advertising sales can properly be attributed to the reorganization, it would be most helpful to find out which of the following?

(A) What proportion of the total revenue of the Greenvile Times is generated by advertising sales?
(B) Has the circulation of the Greenvile Times increased substantially in the last two years?
(C) Among all types of industry and retailing that use the Greenvile Times as an advertising vehicle, which type accounts for the largest proportion of the newspaper’s advertising sales?
(D) Do any clients of the sales representatives of the Greenvile Times have a standing order with the Times for a fixed amount of advertising per month?
(E) Among the advertisers in the Greenvile Times are there more types of retail business or more types of industrial business?