Microsoft 365 Endpoint Administrator Exam Prep 2026 (MD-102)

The requirement for users to register their mobile number during the password reset setup directly relates to the method of authentication used to verify their identity. SMS authentication is the correct choice because it involves sending a one-time code or verification link to the registered mobile number, which the user must then enter to complete the authentication process. This method ensures that the user has access to their mobile device and can receive the SMS.

In contrast, email authentication relies on receiving a verification code via email, which does not require the user to have registered their mobile number. Security questions authentication involves answering predetermined questions which, while secure, do not provide the additional layer tied directly to a mobile number. The Microsoft Authenticator app notification provides a different mechanism for authentication based on an app installed on the user's device, again not necessarily ensuring that a mobile number is registered during the password reset setup.

Thus, SMS authentication is specifically tailored to require the registration of a mobile number, making it essential for the desired functionality in the context of password reset security measures.