When an auditor tests the internal controls of a computerized accounting system, which of the following is true of the test data approach?

A$.$ Test data are coded to a dummy subsidiary so they can be extracted from the system under actual operating conditions.

B$.$ Test data programs need not be tailor$-$made by the auditor for each client's computer applications.

C$.$ Test data programs usually consist of all possible valid and invalid conditions regarding compliance with internal controls.

D$.$ Test data are processed with the client's computer and the results are compared with the auditor's predetermined results.