18. Manager: Accounting and Billing are located right next to each other and the two departments do similar kinds of work; yet expenditures for clerical supplies charged to Billing are much higher. Is Billing wasting supplies?
Head of Billing: Not at all.
Which of the following, if true, best supports the position of the Head of Billing?
(A) There are more staff members in Accounting than in Billing.
(B) Two years ago, expenditures in Accounting for clerical supplies were the same as were expenditures that year in Billing for clerical supplies.
(C) The work of Billing now requires a wider variety of clerical supplies than it did in the past.
(D) Some of the paper-and-pencil work of both Accounting and Billing has been replaced by work done on computers.
(E) Members of Accounting found the clerical supplies cabinet of Billing more convenient to go to for supplies than their own department’s cabinet.

By POE I got to choice E, which happens to be the OA, fortunately.
But can anyone explain what this means "clerical supplies cabinet of Billing more convenient to go to for supplies than their own department’s cabinet"
I did not understand this.