You need to ensure that RODC1 has a directory partition of contoso.com

Your network contains an Active Directory forest named contoso.com. The functional level of
the forest is Windows Server 2008 R2. The DNS zone for contoso.com is Active Directoryintegrated.
You deploy a read-only domain controller (RODC) named RODC1.
You install the DNS Server server role on RODC1.
You discover that RODC1 does not have any application directory partitions.
You need to ensure that RODC1 has a directory partition of contoso.com.
What should you do?

A.
From DNS Manager, create secondary zones.

B.
Run Dnscmd.exe, and specify the /enlistdirectorypartition parameter.

C.
From DNS Manager, right-click RODC1 and click Update Server Data Files.

D.
Run Dnscmd.exe and specify the /createbuiltindirectorypartitions parameter.

Explanation:
http://technet.microsoft.com/en-us/library/cc742490.aspx
RODC Post-Installation Configuration
If you install DNS server after the AD DS installation, you must also enlist the RODC in the
DNS application directory partitions. The RODC is not enlisted automatically in the DNS
application directory partitions by design because it is a privileged operation. If the RODC

were allowed to enlist itself, it would have permissions to add or remove other DNS servers
that are enlisted in the application directory partitions.
To enlist a DNS server in a DNS application directory partition
1. Open an elevated command prompt.
2. At the command prompt, type the following command, and then press ENTER:
dnscmd<ServerName> /EnlistDirectoryPartition <FQDN>
For example, to enlist RODC01 in the domain-wide DNS application directory partition in a
domain named child.contoso.com, type the following command:
dnscmd RODC01 /EnlistDirectoryPartition DomainDNSZones.child.contoso.com