The best answer is D. To structure IT projects to achieve desired business results.

ISACA guidance describes enterprise architecture as a top-down, business-driven discipline focused on business capabilities, strategy, and alignment of people, process, and technology. Enterprise architecture is not primarily about individual systems or day-to-day operations. Its purpose is to ensure that change initiatives and IT investments are organized in a way that supports the enterprise’s strategic and business outcomes.

Option A is too narrow because EA is broader than designing single systems. Option B is only one specialized area within the overall architecture landscape. Option C is more aligned with operations management than enterprise architecture. The strongest answer is the one linking EA to business-driven structuring of initiatives and results.

Therefore, the correct answer is D, because enterprise architecture exists to align and structure IT initiatives so the organization can achieve desired business results.

References (Official ISACA):

ISACA, Developing Business Capabilities Using COBIT 5 — enterprise architecture focuses on business capabilities supporting strategy.

ISACA Journal, Enterprise Security Architecture—A Top-down Approach — architecture bridges business risk, process requirements, and technical issues.

ISACA Journal, Information Security Architecture: Gap Assessment and Prioritization — supports business-driven architectural alignment.

ISACA, Using COBIT 2019 to Plan and Execute an Organization Transformation Strategy — IT governance and management should create value from IT initiatives.