Your network contains an on-premises Active Directory Domain Services (AD DS) domain.

The correct answer is Hybrid join the devices. The devices already belong to an on-premises AD DS domain and run Windows 11, so the lowest-impact approach is to configure Microsoft Entra hybrid join. A Microsoft Entra hybrid joined device remains joined to the on-premises AD DS domain while also being registered in Microsoft Entra ID, which is the correct identity state for existing domain-joined Windows devices that need cloud access with single sign-on behavior. Microsoft’s hybrid join guidance shows that Microsoft Entra Connect can be used to configure Microsoft Entra hybrid join through Configure device options, minimizing manual device-by-device work.

Password hash synchronization and pass-through authentication are user sign-in methods; they do not by themselves join or register the Windows 11 devices to Microsoft Entra ID. They address how credentials are validated, not whether the device has a cloud device identity for seamless access. Joining the devices directly to the tenant would mean Microsoft Entra joining them, which is more disruptive for existing AD DS domain-joined devices. Microsoft Entra joined devices are joined only to Microsoft Entra ID, while hybrid joined devices are intended for organizations that still use on-premises AD DS.

Therefore, select C. Hybrid join the devices.