Your network contains an Active Directory forest. The forest contains two Active Directory domains
named contoso.com and child.contoso.com. The forest functional level is Windows Server 2003. The
functional level of both domains is Windows Server 2008.
The forest contains three domain controllers. The domain controllers are configured as shown in the
following table.
DC1 and DC2 have the DNS Server server role installed and are authoritative for both contoso.com and
child.contoso.com.
The child.contoso.com domain contains a server named serverl.child.contoso.com that runs Windows
Server 2012.
You plan to deploy server1.child.contoso.com as a read-only domain controller (RODC).
You run the adprep.exe /rodcprep command on DC3 and receive the following error message:
You need to identify what prevents you from successfully running Adprep /rodcprep on DC3.
What should you identify?
A.
The domain functional level of child.contoso.com is set to the wrong level.
B.
DC3 cannot connect to the infrastructure master on DC2.
C.
DC3 cannot connect to the domain naming master on DC1.
D.
The forest functional level is set to the wrong level.
Explanation:
Adprep could not contact a replica…
This problem occurs when the Adprep /rodcprep command tries to contact the infrastructure master for
each application partition in the forest. Error message when you run the “Adprep /rodcprep” command in Windows Server 2008:
“Adprep could not contact a replica for partition DC=DomainDnsZones,DC=Contoso,DC=com”
https://support.microsoft.com/en-us/kb/949257