Business rules and Power Apps component framework controls address the two extensibility requirements while minimizing unnecessary server-side code. A business rule implements supported validation or form/table logic declaratively, making it preferable to a plug-in when the requirement can be satisfied without custom server execution. A Power Apps component framework control packages a reusable custom user-interface component that can be deployed in a solution and used across supported applications. A JavaScript web resource can customize form behavior but is not the preferred reusable control framework for a component with its own rendering and lifecycle. A sitemap controls model-driven app navigation and does not implement either reusable UI or business logic. A plug-in is valid for transactions that require server-side execution, but the case explicitly says to minimize that approach. The AB-410 Study Guide explicitly includes “recommend extensibility options.” Selecting a declarative rule and a PCF control applies that objective to the distinct logic and UI requirements.

Study Guide reference/topic: “Design Power Platform solutions — Recommend extensibility options.” AB-410 Study Guide | Microsoft Learn technical reference