According to the ISACA's Information Security Governance Guidance for Boards of Directors and Executive Management, the highest level of maturity of an information security program is Level 5: Optimized, which means that the program is aligned with the business objectives and strategy, and continuously monitors and improves its performance and effectiveness. A framework is in place to measure risks and track effectiveness, and the program is proactive, adaptive, and innovative.
The other options represent lower levels of maturity:
* A training program is in place to promote information security awareness. This is Level 2: Repeatable, which means that the program has some basic policies and procedures, and provides awareness training to employees.
* Information security policies and procedures are established. This is Level 3: Defined, which means that the program has formalized policies and procedures, and assigns roles and responsibilities for information security.
* The program meets regulatory and compliance requirements. This is Level 4: Managed, which means that the program has established metrics and reporting mechanisms, and complies with relevant laws and regulations.
References: : ISACA. (2001). Information Security Governance Guidance for B

The answer B is correct because the most important thing for an IS auditor to review when determining whether IT investments are providing value to the business is the business strategy. The business strategy is the plan or direction that guides the organization's decisions and actions to achieve its goals and objectives.
The business strategy defines the organization's vision, mission, values, competitive advantage, target market, value proposition, and key performance indicators (KPIs).
IT investments are the expenditures or costs incurred by the organization to acquire, develop, maintain, or improve its IT assets, such as hardware, software, network, data, or services. IT investments can help the organization to support its business processes, operations, functions, and capabilities. IT investments can also help the organization to create or enhance its products, services, or solutions for its customers or stakeholders.
To determine whether IT investments are providing value to the business, an IS auditor needs to review how well the IT investments align with and contribute to the business strategy. Alignment means that the IT investments are consistent and compatible with the business strategy, and that they support and enable the achievement of the strategic goals and objectives. Contribution means that the IT investments are effective and efficient in delivering the expected outcomes and benefits for the business, and that they generate a positive return on investment (ROI) or value for money.
An IS auditor can use various methods or frameworks to review the alignment and contribution of IT investments to the business strategy, such as:
* Balanced scorecard: A balanced scorecard is a tool that measures and monitors the performance of an organization across four perspectives: financial, customer, internal process, and learning and growth. A balanced scorecard can help an IS auditor to evaluate how well the IT investments support and improve each perspective of the organization's performance, and how they link to the organization's vision and strategy.
* Value chain analysis: A value chain analysis is a tool that identifies and analyzes the primary and support activities that add value to an organization's products or services. A value chain analysis can help an IS auditor to assess how well the IT investments enhance or optimize each activity of the value chain, and how they create or sustain a competitive advantage for the organization.
* Business case analysis: A business case analysis is a tool that evaluates the feasibility, viability, and desirability of a proposed project or initiative. A business case analysis can help an IS auditor to examine how well the IT investments address a business problem or opportunity, how they deliver the expected benefits and outcomes for the stakeholders, and how they compare with alternative options or solutions.
The other options are not as important as option B. Return on investment (ROI) (option A) is a metric that measures the profitability or efficiency of an investment by comparing its benefits or returns with its costs or expenses. ROI can help an IS auditor to quantify the value of IT investments for the business, but it does not capture all aspects of value, such as quality, satisfaction, or impact. ROI also depends on how well the IT investments align with the business strategy in the first place. Business cases (option C) are documents that justify and support a proposed project or initiative by describing its objectives, scope, benefits, costs, risks, and alternatives. Business cases can help an IS auditor to understand the rationale and expectations for IT investments, but they do not guarantee that the IT investments will actually deliver the desired value for the business. Business cases also need to be aligned with the business strategy to ensure their relevance and validity. Total cost of ownership (TCO) (option D) is a metric that measures the total costs incurred by an organization to acquire, operate, maintain, and dispose of an IT asset over its life cycle. TCO can help an IS auditor to estimate the financial impact of IT investments for the business, but it does not reflect the benefits or outcomes of IT investments, nor does it indicate how well the IT investments support or enable the business strategy.
References:
* IT Strategy: Aligning IT & Business Strategy
* How To Measure The Value Of Your Technology Investments
* IT Investment Management: A Framework for Assessing ... - GAO
* How To Align Your Technology Investments With Your Business Strategy

A digital signature is a cryptographic technique that uses the sender's private key to generate a unique code for a message or document. The receiver can use the sender's public key to verify the authenticity and integrity of the message or document. A digital signature can prevent unauthorized change, as any modification to the message or document will invalidate the signature and alert the receiver of tampering.
References
What is a digital signature?
Digital Signature - an overview | ScienceDirect Topics
ISACA CISA Review Manual, 27th Edition, page 253

The greatest concern associated with a high number of IT policy exceptions approved by management is that the exceptions may result in noncompliance. IT policy exceptions are deviations from the established IT policies that are granted by management for specific reasons and circumstances. However, if there are too many exceptions, it may indicate that the IT policies are not aligned with the business needs, regulatory requirements, or best practices. This may expose the organization to legal, contractual, or reputational risks due to noncompliance. The other options are not as concerning as noncompliance, as they do not have the same potential impact or consequences. The exceptions are likely to continue indefinitely is a possible outcome of a high number of exceptions, but it does not necessarily imply a negative effect on the organization. The exceptions may elevate the level of operational risk is a valid concern, but it can be mitigated by implementing compensating controls or monitoring mechanisms. The exceptions may negatively impact process efficiency is a minor concern, as it does not affect the effectiveness or reliability of the IT processes. References: CISA Review Manual (Digital Version), Chapter 3, Section 3.2

Collaborative discussions help address the auditee's concerns, find mutually agreeable solutions, and create buy-in for implementing improvements.
References
ISACA CISA Review Manual (Current Edition) - Chapters on audit reporting and communication Auditing Standards - Emphasize the importance of understanding and addressing auditee concerns.