The best way to improve the visibility of end-user computing (EUC) applications that support regulatory reporting is to maintain an EUC inventory, as this provides a comprehensive and up-to-date list of all EUC applications, their owners, their locations, their purposes, and their dependencies. An EUC inventory can help identify and manage the risks associated with EUC applications, such as data quality, security, compliance, and continuity. EUC availability controls, EUC access control matrix, and EUC tests of operational effectiveness are important for ensuring the reliability and security of EUC applications, but they do not improve the visibility of EUC applications as much as an EUC inventory. References: CISA Review Manual (Digital Version), Chapter 3: Information Systems Acquisition, Development and Implementation, Section
3.4: End-user Computing

The auditor should first escalate to audit management to discuss the audit plan. This is because the audit plan should be based on a risk assessment and aligned with the organization's objectives and strategies. The auditor should not accept the CIO's request without proper justification and approval from the audit management, who are responsible for ensuring the audit plan's quality and independence. The auditor should also communicate the potential risks and implications of not conducting IS audits in the upcoming year, such as missing new or emerging threats, vulnerabilities, or compliance issues. References:
* CISA Review Manual (Digital Version), Chapter 2, Section 2.11
* CISA Online Review Course, Domain 1, Module 1, Lesson 22

A Disaster Recovery as a Service (DRaaS) provider is responsible for system recovery procedures, including restoring systems and services in a disaster scenario. This is the core functionality of DRaaS.
* Stakeholder Communications (Option B): This is typically managed internally by the organization to ensure alignment with its crisis management plan.
* Validation of Recovered Data (Option C): The organization must verify data integrity to meet business requirements.
* Maintaining Currency of Data (Option D): While DRaaS may handle data backups, the organization retains responsibility for ensuring the relevance of the data being backed up.
Reference: ISACA CISA Review Manual, Job Practice Area 4: Protection of Information Assets.

The auditor's best action is to re-perform the audit before changing the conclusion, because the auditor needs to obtain sufficient and appropriate evidence to support the audit opinion. The evidence provided by IT management may not be reliable or relevant, and it may not reflect the actual effectiveness of the control during the audit period. Therefore, the auditor should verify the evidence independently and test the control again to ensure that it meets the audit criteria and objectives. The other options are not appropriate, because they either ignore or accept the evidence provided by IT management without verification, which may compromise the quality and integrity of the audit. References:
* ISACA, CISA Review Manual, 27th Edition, chapter 1, section 1.51
* ISACA, IT Audit and Assurance Standards, Guidelines and Tools and Techniques for IS Audit and Assurance Professionals, section 12062