Auditors use the _______________ as a reference to determine conformity.

The correct answer is "Audit criteria," as auditors rely on established standards, policies, or requirements to assess whether an organization's processes and controls conform to expected norms or regulations. Audit criteria provide a framework against which evidence can be evaluated, helping auditors to determine if the practices in place meet specific requirements, such as those set forth by ISO/IEC 27001 or other relevant standards.

In the context of an ISO/IEC 27001 audit, the criteria may include the standard itself, internal policies, regulatory requirements, and contractual obligations related to information security. Using these criteria, auditors can systematically review documentation, interview staff, and observe practices to judge conformity.

The other options do not fulfill the role of providing a reference for conformity determination. Audit feasibility refers to the practicality of conducting an audit based on various factors. Audit objectives outline what the audit aims to achieve, which is broader than assessing conformity. Audit scope defines the boundaries of the audit, such as which areas or departments are included, but does not provide the standards or benchmarks needed to assess conformity.