Select which groups must map to UNIX GIDs on a Samba server operating as a PDC. (Select TWO correct answers.)

'Domain Administrators' is an important group, but its mapping is not strictly mandated for basic PDC functionality in the same way as core user and guest groups.

The 'Domain Users' group is a fundamental group for any Windows domain, including those emulated by Samba as a PDC, and its mapping to a Unix GID is necessary to provide standard user access and permissions.

The 'Domain Guests' group is also a mandatory group that must be mapped to a Unix GID on a Samba PDC to properly handle guest user permissions and access rights with limited privileges.

'Domain Controllers' is a group related to managing domain controllers themselves and is not a general user group requiring mandatory GID mapping for user access on a Samba PDC.

'Domain Operators' is an optional administrative group with specific delegated permissions, and its mapping is not a core requirement for basic Samba PDC operation unlike Domain Users or Guests.