A. Labels, both external and internal, are used to identify a file. External labels are the gummed labels attached to the outside of a disk or other media that identify its contents. Internal labels identify the contents by means of an identification within the data file that can be read by the computer.

B. Processing controls are controls designed to ensure that processing has occurred properly and that no transactions have been lost or incorrectly added. Control totals are of various kinds, but they all involve comparison of counts at various points with the correct count. A limit check, or a reasonableness check, tests a value to determine whether it falls within a prescribed range. A sequence test verifies that records are in the correct sequence.

C. While authorization of data, approval of data, and screening of data are controls, they are not controls that are used during the processing of the data.

D. While review of data output by data control groups is a control, it is not a control that is used during the processing of the data.