Which of the following is likely to be the most important disadvantage of using concurrent auditing techniques?

a. They can provide evidence about only a limited set of features in an application system that interest the auditor

b. Only a few types of application systems can accommodate the audit modules needed to collect the evidence

c. Auditors need to be highly skilled to interpret the output produced by concurrent auditing techniques

d. They require a sustained commitment by management, auditors, and information systems staff to their ongoing maintenance and use