Which users must sign in from a computer joined to adatum.com?

Your on-premises network contains an Active Directory domain named adatum.com that is synced to Azure Active Directory (Azure AD). Password writeback is disabled.

In adatum.com, you create the users shown in the following table.

Which users must sign in from a computer joined to adatum.com?
A . User2 only
B . User1 and User3 only
C . User1, User2, and User3
D . User2 and User3 only
E . User1 only

Answer: E

Explanation:

Password writeback is a feature enabled with Azure AD Connect that allows password changes in the cloud to be written back to an existing on-premises directory in real time.

References: https://docs.microsoft.com/en-us/azure/active-directory/authentication/concept-sspr-writeback