A compliance gap analysis is a detailed review of an organization's current state of compliance against a specific regulation or standard. It helps identify the areas and controls that are not meeting the requirements, assess their risk levels, and determine the corrective actions that can be taken to achieve compliance12. A compliance gap analysis is the most useful tool for an IS auditor to review when auditing against a new regulation, as it provides a clear and comprehensive picture of the compliance status, gaps, and remediation plan of the organization.
References
1: Information Security Architecture: Gap Assessment and Prioritization - ISACA
2: How to perform Compliance Gap Analysis? - Sprinto

Regular scanning of hard drives is the most effective way to detect installation of unauthorized software packages by employees because it can identify any software that is not approved by the organization and may pose a security risk or violate the software policy. Communicating the policy to employees is important, but it may not prevent or detect unauthorized software installation. Logging of activity on the network can monitor network traffic, but it may not capture all software installation events. Maintaining current antivirus software can protect the system from malicious software, but it may not detect all unauthorized software packages. References:
* ISACA, CISA Review Manual, 27th Edition, 2020, p. 2381
* ISACA, CISA Review Questions, Answers & Explanations Database - 12 Month Subscription

The best action that audit management should consider first is to reassign the audit to an internal audit subject matter expert. This is because cloud service audits require specialized knowledge and skills to assess the risks and controls associated with the cloud service provider and the cloud service customer. An IS auditor who is unfamiliar with the technologies in use and their associated risks to the business may not be able to perform an effective and efficient audit, and may miss important issues or provide inaccurate recommendations.
Therefore, it is important to ensure that the IS auditor assigned to the cloud service audit has the appropriate competence and experience.
The other options are not as good as reassigning the audit to an internal audit subject matter expert.
Conducting a follow-up audit after a suitable period has elapsed may not address the quality issues of the initial audit, and may also delay the identification and remediation of any problems. Rescheduling the audit assignment for the next financial year may expose the organization to unnecessary risks and may not meet the audit objectives or expectations. Extending the duration of the audit to give the auditor more time may not be feasible or cost-effective, and may not guarantee that the auditor will acquire the necessary knowledge and skills in time.
References:
ISACA, CISA Review Manual, 27th Edition, 2019, p. 1391
ISACA, Cloud Computing: Business Benefits With Security, Governance and Assurance Perspectives, 2009, p. 14

The audit charter is a document that defines the purpose, scope, authority, and responsibility of an IT audit organization. The audit charter should specify roles and responsibilities within an IT audit organization, such as who is accountable for approving the audit plan, who is responsible for conducting the audits, who is authorized to access the audit evidence, and who is accountable for reporting the audit results. The organizational chart, the engagement letter, and the annual audit plan are also important documents for an IT audit organization, but they do not specify roles and responsibilities as clearly and comprehensively as the audit charter.