The defining capability of an IDP is enabling self-service so developers can independently access infrastructure and platform resources. Option D is correct because self-service resource provisioning APIs allow developers to provision resources such as namespaces, databases, or environments without relying on manual intervention from the platform team. These APIs embed governance, compliance, and organizational guardrails while giving autonomy to development teams.

Option A (manual deployment services) defeats the purpose of self-service. Option B (knowledge centers) improve documentation but do not provide automation. Option C (logging/monitoring interfaces) are observability tools, not resource provisioning mechanisms.

Self-service APIs empower developers, reduce cognitive load, and minimize bottlenecks. They also align with the platform engineering principle of “treating the platform as a product,” where developers are customers, and the platform offers curated golden paths to simplify consumption of infrastructure and services.