Which of the following statements about the costs and benefits of using test data as an audit evidence-collection tool is true?

a. Black-box testing tends to be a more effective test-data design strategy than white-box testing

b. A major advantage of using test data to collect evidence is that auditors require little technical competence with computers to use it effectively

c. The most effective test-data design strategy might be to have two auditors work independently to conduct testing and to pool their results than to have them work together during testing

d. Use of test data to collect audit evidence will take less time than code review, but it is less effective at identifying program defects