An App registration acts as the global definition or template for an application. It's where a developer defines the application's identity, including its name, supported account types, and redirect URIs. When an application is granted consent to access a specific tenant, a service principal object is created. This service principal is represented as an "Enterprise application" in the Microsoft Entra admin center UI. The Enterprise application is the local instance within that tenant, used for managing access, assigning users and groups, and configuring single sign-on (SSO) and conditional access policies.

A. They are distinct, related objects. An app registration is the global blueprint, while an enterprise app is the local instance (service principal) in a tenant.

B. This reverses the concepts. App registrations define the application's technical details like reply URLs, while Enterprise apps handle user assignments and access policies.

D. Security groups are used to assign permissions to Enterprise apps; they are a mechanism for access control but do not replace the application objects themselves.

1. Microsoft Learn. "Application and service principal objects in Microsoft Entra ID." Microsoft Entra documentation. Section: "Relationship between application registration

application objects

and service principals." This document explicitly states

"The application registration is the global representation of your application... A service principal is the local representation

or application instance

of a global application object in a single tenant."

2. Microsoft Learn. "Quickstart: Register an application with the Microsoft identity platform." Microsoft Entra documentation. This guide walks through the process of creating an App registration

defining its core identity properties.

3. Microsoft Learn. "Managing enterprise applications." Microsoft Entra documentation. This section covers the management of service principals (Enterprise apps) within a tenant

including user assignment and SSO configuration.