Phishing exploits human weaknesses by tricking users into revealing sensitive information. While technical defenses (IDS, firewalls, hardening) help, the most effective prevention is regular security awareness training that educates employees on recognizing and avoiding phishing attempts. Therefore, the best preventive measure is Option C.

Adding invoices to the computer program to assess the reliability and effectiveness of the review process and whether controls work best describes an internal auditor's use of test data. This approach involves introducing test data into the system to evaluate how well the system processes invoices and whether it effectively identifies and prevents questionable invoices from being processed for payment.
IIA Standards: 1220.A2 - Proficiency and Due Professional Care
IIA Practice Guide: Use of Technology in Auditin

According to IIA guidance, the chief audit executive (CAE) should maintain independence and objectivity in their role. While the CAE can manage and coordinate risk management processes, audit those processes, and be involved in risk oversight committees, they should not accept management's responsibility for risk management without the board's approval. This ensures that there is no conflict of interest and maintains the CAE's independence. References:
* IIA Standards - 1110: Organizational Independence
* IIA Practice Advisory - 2060-1: Reporting to Senior Management and the Board

The organization and content of workpapers should be based on the professional judgment of the internal auditor. Workpapers should provide sufficient detail to support the audit findings and conclusions but do not need to answer every conceivable question. Standard 2330 - Documenting Information states that internal auditors must document relevant information to support the conclusions and engagement results. This allows for flexibility and professional judgment in determining what is necessary and appropriate to include.
Institute of Internal Auditors (IIA), International Standards for the Professional Practice of Internal Auditing (Standards), Standard 2330 - Documenting Information.

To immediately enhance and maintain long-term IT audit quality, inviting qualified staff from the IT department to serve as guest auditors is a viable solution. This approach provides immediate access to IT expertise, ensuring high-quality audits. Additionally, it fosters collaboration between the IT and internal audit departments, promotes knowledge transfer, and helps build internal audit staff capabilities over time. This method is both cost-effective and sustainable, compared to contracting external specialists continuously.
The Institute of Internal Auditors (IIA) - Standards for the Professional Practice of Internal Auditing, Standard
1210 - Proficiency and Standard 2230 - Engagement Resource Allocation