Hi, Emily -

This is a "hidden assumption" question. Questions of this type present you with an argument that sounds superficially plausible, but which is invalid unless some additional unstated assumption is true. Your job is to identify which of the five answers articulates the assumption.

In this case, the problem is with the premise, "our company and four other companies together account for 60% of the total." This sounds very bad, but in fact tells us nothing at all about our company's output of pollutants. To see this, suppose that our company magically produces no pollutants at all. Can the premise still be true? Sure it can -- if the other four together produce the entire 60%. The conclusion depends on the hidden assumption that our share of the 60% is significant. Only answer [D] articulates this.

(Note that the argument also depends on the assumption that the study is accurate; however, none of the answers articulates this assumption. [A] might seem to indirectly do so, but does not: the presence or absence of hostility toward the industry as a whole does not directly bear on the accuracy of statistics.)

Hope this helps! Please post again if you still have questions.

Best,
Lyn