Explanation:
An external email address can be used to authenticate self-service password reset (SSPR). # Yes A notification to the Microsoft Authenticator app can be used to authenticate self-service password reset (SSPR). # Yes To perform self-service password reset (SSPR), a user must already be signed in and authenticated to Azure AD. # No For Microsoft Entra self-service password reset (SSPR), users must register one or more authentication methods that can later be used when they forget their password or are locked out. Microsoft's end-user guidance states that an email address option lets users configure "an alternate email address that can be used without requiring your forgotten or missing password," and that this method is available only for password reset. In practice, this alternate address is typically a personal or external email (for example, Gmail), so using an external email to authenticate SSPR is valid.
SSPR can also use the Microsoft Authenticator app as an authentication method. Microsoft documents that Authenticator push notifications, including number matching, are supported for several scenarios, explicitly listing self-service password reset (SSPR) among them. This means a push notification to the app on the user' s device can be used to verify identity during SSPR.
Finally, SSPR is designed for situations where the user cannot sign in. Official SSPR process descriptions explain that users start from the "Can't access your account?" or password-reset page, provide their username, and then use their registered methods to prove identity. They do not need to be already authenticated to Azure AD; SSPR exists precisely to recover access when sign-in fails.

In Microsoft Entra ID (formerly Azure AD), self-service password reset (SSPR) is the feature that explicitly supports email as an authentication method when users need to verify their identity to reset or unlock their password.
According to Microsoft's identity and access documentation and the SCI learning content, SSPR lets administrators choose which verification methods are available to users, such as mobile phone, office phone, mobile app, security questions, and email. When email is enabled, a verification code can be sent to a registered alternate email address. The user proves their identity by entering this code, which is treated as an authentication step in the SSPR process.
By contrast:
Microsoft Entra Multi-Factor Authentication (MFA) does not support email as an MFA method; it focuses on methods like authenticator apps, phone calls, and text messages.
Microsoft Entra ID Protection detects and responds to risky sign-ins and users but does not provide email- based authentication.
Microsoft Entra Password Protection deals with banned and compromised passwords, not with email verification.
Therefore, the only option in the list that uses email as a supported authentication method is self-service password reset (SSPR).

Explanation:

Microsoft Entra ID (formerly Azure Active Directory) is a cloud-based directory and identity platform. In Microsoft's SCI materials, Entra ID is described as "Microsoft's cloud-based identity and access management service that helps your employees sign in and access resources," underscoring that it's not deployed on- premises; instead, organizations can synchronize or federate with on-premises Active Directory using tools like Entra Connect. The same documentation explains that Entra ID is included with Microsoft 365 subscriptions, providing tenant identity services for apps such as Exchange Online, SharePoint Online, and Teams. Core capabilities listed include authentication, single sign-on (SSO), Conditional Access, device registration, and application access management, all of which classify Entra ID as an identity and access management (IAM) service. Thus: (1) on-premises deployment - No (it's cloud-native), (2) provided with Microsoft 365 - Yes (a directory is created for each tenant), and (3) IAM service - Yes (it delivers identity, access, and governance controls used across Microsoft cloud services).

In Microsoft's hybrid identity guidance, Azure AD Connect is the supported tool to bridge on-premises Active Directory Domain Services (AD DS) with Azure Active Directory (Azure AD). Microsoft Learn describes it plainly: "Azure AD Connect is Microsoft's tool for connecting on-premises directories to Azure AD." It "synchronizes user, group, and device objects" so cloud identities stay aligned with on-premises accounts and attributes. Azure AD Connect also supports multiple sign-in methods: "password hash synchronization, pass-through authentication, and federation integration." In other words, you can sync identities and choose how users authenticate to Microsoft Entra ID (Azure AD).
By contrast, Active Directory Federation Services (AD FS) is a federation service used for claims-based authentication; it does not perform directory synchronization. Azure Sentinel (now Microsoft Sentinel) is a cloud-native SIEM/SOAR and is unrelated to identity sync. Privileged Identity Management (PIM) is an identity governance feature for just-in-time privileged access; it does not synchronize identities. Therefore, in a hybrid identity model where the requirement is to sync identities between AD DS and Azure AD, the correct Microsoft-endorsed solution is Azure AD Connect, which "keeps identities in sync between on-premises directories and Azure AD."