Which of the following persons is responsible for testing and verifying whether the security policy is properly implemented, and the derived security solutions are adequate or not? Response:

An auditor's primary role is to conduct independent assessments and examinations of an organization's systems, processes, and controls to determine compliance with policies, standards, and regulations. This includes testing and verifying the proper implementation of security policies and the adequacy of security solutions to identify any gaps or deficiencies.

A user is an end-consumer of the system and is not typically responsible for auditing its security.

A data custodian is responsible for the technical implementation and maintenance of security controls for data, not for independent verification.

A data owner is responsible for the overall classification, protection, and risk acceptance for data, but does not typically perform the auditing function.