Microsoft Entra ID is a cloud-based identity and access management (IAM) service. Its primary function is to serve as an identity provider (IdP). It manages user identities and facilitates secure access to resources by handling authentication (verifying a user's identity, typically through sign-in) and authorization (granting the verified user appropriate permissions). The other options represent different categories of services: Microsoft Sentinel is a SIEM, Microsoft Defender XDR is an XDR system, and management groups are an Azure resource hierarchy construct.

Microsoft Entra documentation: "Microsoft Entra ID is a cloud-based identity and access management (IAM) solution... Microsoft Entra ID enables your employees to securely access both external and internal resources. It is the central point for managing identities and access control."

Source: Microsoft. (2024). What is Microsoft Entra ID?. Microsoft Learn. Retrieved from https://learn.microsoft.com/en-us/entra/fundamentals/whatis (Introduction section).

Microsoft Entra documentation on federation: "Microsoft Entra ID can act as the identity provider (IdP) for applications."

Source: Microsoft. (2023). Federation with a SAML/WS-Fed identity provider (IdP) for B2B. Microsoft Learn. Retrieved from https://learn.microsoft.com/en-us/entra/external-id/direct-federation (Overview section).

Microsoft Sentinel documentation: "Microsoft Sentinel is a scalable, cloud-native solution that provides security information and event management (SIEM) and security orchestration, automation, and response (SOAR)."

Source: Microsoft. (2024). What is Microsoft Sentinel?. Microsoft Learn. Retrieved from https://learn.microsoft.com/en-us/azure/sentinel/overview (Introduction section).