Your network contains a single Active Directory domainnamed contoso.com.
An administrator accidentally deletes the _msdsc.contoso.com zone.
You recreate the _msdsc.contoso.com zone.
You need to ensure that the _msdsc.contoso.com zone contains all of the required DNS records.
What should you do on each domain controller?

A.
Restart the Netlogon service.

B.
Restart the DNS Server service.

C.
Run dcdiag.exe /fix.

D.
Run ipconfig.exe /registerdns.

Explanation:
Reference 1:
http://support.microsoft.com/kb/817470
To register the required records to the single rootdomain controller, restart the Net Logon service on all the
domain controllers. The replication works correctlyif the replication window is not less than the default DNS
Time to Live (TTL) entry. To restart the Net Logon service, follow these steps:
1. Click Start, click Run, type cmd in the Open box,and then press ENTER.
2. At the command prompt, type the following command, and then press ENTER: net stop netlogon
3. Type net start netlogon, and then press ENTER.
Reference 2:
http://serverfault.com/questions/383915/how-do-i-manually-create-the-msdcs-dns-zone-for-a-domain-that-wascreated-pre-s
Be sure to restart the Netlogon services on all DC’s when the zone has been replicated to them. This forces the
DC’s to register their SRV records in the _msdcs zone.