Your network contains a single Active Directory domain named contoso.com. The domain contains two domain controllers named DC1 and DC2 that run Windows Server 2008 R2.   DC1 hosts a primary zone for contoso.com. DC2 hosts a secondary zone for contosto.com.   On DC1， you change the zone to an Active Directory-integrated zone and configure the zone to accept  secure dynamic updates only.   You need to ensure that DC2 can accept secure dynamic updates to the contoso.com zone.  Which command should you run（）

• A、dnscmd.exe dc2.contoso.com /createdirectorypartition dns.contoso.com
• B、dnscmd.exe dc2.contoso.com /zoneresettype contoso.com /dsprimary
• C、dnslint.exe /ql
• D、repadmin.exe /syncall /force