hi everyone, a CR in princeton. pls help!

leaf

A company that manufactures heavy industrial equipment employs dozens of people in jobs that are considered quite hazardous. The company obeys federal regulations governing workplace safety, and, to comply with new regulations instituted to avoid recently discovered risks from airborne particulate matter, company engineers were required to install extremely expensive air filtering equipment. However, despite the expenses of the air filtering equipment, the company’s operating costs for the quarter were considerably lower than normal.

Which of the following, if true, most helps to resolve the apparent paradox?

(A) Over half the company’s expenditures to maintain worker safety go to pay for protective garments, yet only a small percentage of such expenditures to to pay for nose and mouth filters

(B)  Prior to the installation of the air filtering equipment, the company had had to prevent damage due to particulate contamination of manufacturing equipment.

(C) The company’s costs of labor, which make up a large fraction of operating costs, increased during the same period.

The answer is B

回家过年

I think that A,C are definitely wrong or unrelated to the question.
To resolve the question of explaining the paradox, we should start from the thoughts as follows: 1,the paradox is nonexistent. 2. the paradox is emphasize the different aspects of a theme. I feel that such question relates to the latter one. "for the quarter" is very important and the answer gives a explanation to why "considerably lower than normal" from the other aspect.

But this question is really ticklish.