The advantage of using agile software development methodology over the waterfall methodology is that it allows for quicker deliverables. Agile software development is an iterative and incremental approach that emphasizes customer feedback, collaboration, and adaptation. Agile software development delivers working software in short cycles, called sprints, that typically last from two to four weeks. This enables the development team to respond to changing requirements, deliver value faster, and improve quality. Waterfall software development is a linear and sequential approach that follows a predefined set of phases, such as planning, analysis, design, implementation, testing, and maintenance. Waterfall software development requires a clear and stable definition of the project scope, deliverables, and expectations before starting the development process. Waterfall software development can be slow, rigid, and costly, especially if changes occur during the later stages of the project. References: CISA Review Manual (Digital Version), Chapter 3:
Information Systems Acquisition, Development & Implementation, Section 3.1: Project Management Practices

Backup procedures for an organization's critical data are considered to be corrective controls, as they are designed to restore normal operations after a disruption or failure. Corrective controls aim to minimize the impact of an incident and prevent recurrence. Directive, detective and compensating controls are not related to backup procedures. Directive controls are intended to guide or instruct users to follow policies and procedures. Detective controls are intended to identify and report incidents or violations. Compensating controls are intended to mitigate the risk of a missing or ineffective primary control. References: CISA Review Manual (Digital Version), Chapter 2, Section 2.11

Comprehensive and Detailed Step-by-Step Explanation:
For online payment security, bothconfidentiality(protection of data) andnonrepudiation(ensuring the sender cannot deny a transaction) are essential.
* Option A (Incorrect):DES is outdatedandinsecurefor modern encryption needs. It has been replaced by stronger algorithms.
* Option B (Incorrect):AES provides strong encryption(confidentiality) but does not handlenonrepudiationon its own.
* Option C (Correct):PKI (Public Key Infrastructure)is the best solution because it providesencryption for confidentialityanddigital signatures for nonrepudiation, ensuring bothsecuretransactions andauthenticationof parties involved.
* Option D (Incorrect):AVPN secures network traffic, but it does not address nonrepudiation, which is critical in online payments.
Reference:ISACA CISA Review Manual -Domain 5: Protection of Information Assets- Covers encryption, PKI, and secure payment processing.

This is because the follow-up of agreed corrective actions for reported audit issues should be done after the auditee has had enough time to implement the corrective actions and demonstrate their effectiveness and sustainability. The follow-up audit should not be too soon or too late, but based on a reasonable and realistic timeframe that allows for adequate testing and verification of the control operation12.
Answer A. Progress updates indicate that the implementation of agreed actions is on track. is not the best answer, because progress updates are not sufficient to guide the follow-up audit timing. Progress updates are useful for monitoring and communicating the status and challenges of the corrective actions, but they do not provide conclusive evidence of the control operation. The follow-up audit should be based on actual results and outcomes, not on expectations or projections12.
Answer C. Business management has completed the implementation of agreed actions on schedule. is not the best answer, because the completion of the implementation of agreed actions is not enough to guide the follow-up audit timing. The completion of the implementation only indicates that the auditee has taken the necessary steps to address the audit issues, but it does not guarantee that the corrective actions are effective and sustainable. The follow-up audit should be based on the evaluation and validation of the control operation, not on the completion of the control implementation12.
Answer D. Regulators have announced a timeline for an inspection visit. is not the best answer, because the regulators' inspection visit is not relevant to guide the follow-up audit timing. The regulators' inspection visit is an external factor that may or may not coincide with the internal follow-up audit schedule. The follow-up audit should be based on the internal audit plan and objectives, not on the external audit requirements or expectations12.