Cost-benefit analysisis the most effective and practical approach for evaluating the value of cybersecurity investments. It allows comparison of expected benefits (risk reduction, incident cost avoidance, compliance) against the costs (investment, operations).
While NPV and IRR are solid financial tools, they are better suited to revenue-generating projects.
Cybersecurity's value is often intangible or indirect, making a straightforwardcost-benefit frameworkmore suitable.
Reference:
CGEIT Review Manual: Domain 4 - Risk Optimization and Business Case Justification COBIT 2019: EDM02 (Ensure Benefits Delivery).

This is because continuous testing of disaster recovery capabilities can help to evaluate and validate the effectiveness and efficiency of the disaster recovery plan, identify and address any gaps or issues, and implement any improvements or adjustments based on the lessons learned1. Continuous testing can also help to ensure that the disaster recovery plan is aligned with the current and future business needs and expectations, and that the disaster recovery team and stakeholders are familiar and prepared with their roles and responsibilities1.
B). Increased training and monitoring for disaster recovery personnel who perform below expectations. This is not the best way to enable the enterprise to accomplish the objective of improving its disaster recovery capabilities, as it only focuses on one aspect of the disaster recovery plan, which is the human factor. While training and monitoring are important for enhancing the skills and performance of the disaster recovery personnel, they are not sufficient to address the other aspects of the disaster recovery plan, such as the technology, process, and communication factors2. Moreover, increased training and monitoring may not be effective if they are not based on a clear and comprehensive assessment of the disaster recovery capabilities and outcomes.
C). Annual review and updates to the disaster recovery plan (DRP). This is not the best way to enable the enterprise to accomplish the objective of improving its disaster recovery capabilities, as it may not be frequent or timely enough to capture and respond to the changing business environment and requirements. An annual review and update may also be insufficient to test and validate the disaster recovery plan, as it may not cover all possible scenarios or situations that could occur in a real disaster3. A more agile and adaptive approach to reviewing and updating the disaster recovery plan is recommended, such as using a continuous improvement cycle or a stage-gate process4.
D). Increased outsourcing of disaster recovery capabilities to ensure reliability. This is not the best way to enable the enterprise to accomplish the objective of improving its disaster recovery capabilities, as it may introduce new risks and challenges for the enterprise, such as loss of control, dependency, compatibility, security, compliance, and cost issues5. Outsourcing some or all of the disaster recovery capabilities may also reduce the involvement and ownership of the enterprise's internal staff and stakeholders in the disaster recovery planning process, which could affect their commitment and readiness in case of a disaster5. Outsourcing should be carefully considered and evaluated based on the specific needs and circumstances of the enterprise, and should be complemented by a robust governance and management framework5.

The quality assurance process is the set of activities that ensures that the software development process follows the defined standards and meets the customer requirements. The quality assurance process includes planning, designing, executing, and monitoring the tests, as well as reporting and resolving the defects. Evaluating the quality assurance process can help to identify and improve the root causes of software defects, such as inadequate testing techniques, tools, or resources, poor communication or collaboration among stakeholders, or lack of quality control or feedback mechanisms123. References: QA Process: A Complete Guide to QA Stages, Steps, & Tools. What is Software Quality Assurance (SQA): A Guide for Beginners. Software Quality Assurance | Components | Standards | Techniques - EDUCBA.

The first governance action for implementing a BYOD program should be to assess the BYOD risk. This is because BYOD introduces various security, legal, and operational risks to the enterprise, such as data loss or leakage, unauthorized access, malware infection, compliance violation, device management, and user privacy.
Assessing the BYOD risk can help to identify and evaluate the potential threats, vulnerabilities, and impacts of allowing employees to use personal devices for email. Assessing the BYOD risk can also help to determine the appropriate controls and mitigation strategies to reduce the risk to an acceptable level.
Assessing the enterprise architecture (EA) is not the first governance action, as it is a subsequent step after assessing the BYOD risk. EA is a framework that defines the structure, components, relationships, and principles of the enterprise's IT environment. Assessing the EA can help to ensure that the BYOD program aligns with the enterprise's vision, strategy, goals, and standards. However, assessing the EA does not address the specific risks associated with BYOD.
Updating the network infrastructure is not the first governance action, as it is an implementation step after assessing the BYOD risk and EA. Updating the network infrastructure can help to enhance the performance, reliability, scalability, and security of the network that supports the BYOD program. However, updating the network infrastructure does not provide a comprehensive risk assessment or governance framework for BYOD.
Updating the BYOD policy is not the first governance action, as it is a result of assessing the BYOD risk and EA. A BYOD policy is a document that defines the rules, guidelines, and responsibilities for employees who use personal devices for email. Updating the BYOD policy can help to communicate the expectations and requirements for BYOD users and enforce compliance and accountability. However, updating the BYOD policy does not provide a thorough risk analysis or architectural alignment for BYOD.
References := BYOD Best Practices - JumpCloud, Assessing your needs section. End user device security for Bring-Your-Own-Device (BYOD) deployment models - ITSM.70.003 - Canadian Centre for Cyber Security,
1 Introduction section. BYOD Policy Best Practices: The Ultimate Checklist - Scalefusion, Introduction section. The Ultimate Guide to BYOD Security: Definition & More - Digital Guardian, The Challenges of BYOD Security section.

A gap analysis is a method of assessing the differences in performance between a business' information systems or software applications to determine whether business requirements are being met and, if not, what steps should be taken to ensure they are met successfully1. A gap analysis typically involves identifying non-compliant processes or activities; assessing their risk levels; determining potential corrective actions that can be taken to address them; and implementing those corrective measures1. Once completed, organizations can then measure their progress toward achieving full compliance over time1.
A gap analysis should be done first when feedback indicates recently implemented software products are not meeting business unit expectations, as it can help identify the root causes of the dissatisfaction, the gaps between the current and desired state of the software products, and the actions needed to close those gaps. A gap analysis can also help align the software products with the business strategy, goals, and expectations, as well as ensure compliance with regulations and policies.
Reviewing help desk logs, confirming user acceptance testing (UAT) was completed, and instituting a new software training program are also important steps to take when software products are not meeting expectations, but they are not the first step. Reviewing help desk logs can help gather feedback and identify issues or errors with the software products, but it does not provide a comprehensive analysis of the gaps and solutions. Confirming UAT was completed can help verify that the software products were tested by the end users before implementation, but it does not address the reasons why the feedback was negative after implementation. Instituting a new software training program can help improve the user's skills and knowledge of the software products, but it does not guarantee that the software products will meet their needs and expectations.
References := What is Gap Analysis in Compliance | Scytale; How to Perform an IT Gap Analysis - Systems X; IT Gap Analysis - First Step to ITIL Success | Invensis Learning.