Your company has a main office and a branch office. The company has a single-domain Active  Directory forest.   The main office has two domain controllers named DC1 and DC2 that run Windows Server 2008 R2. The branch office has a Windows Server 2008 R2 read-only domain controller （RODC） named DC3.   All domain controllers hold the DNS Server server role and are configured as Active Directory-integrated  zones. The DNS zones only allow secure updates.  You need to enable dynamic DNS updates on DC3.  What should you do（）

• A、Run the Ntdsutil.exe DS Behavior commands on DC3.
• B、Run the Dnscmd.exe /ZoneResetType command on DC3.
• C、Reinstall Active Directory Domain Services on DC3 as a writable domain controller.
• D、Create a custom application directory partition on DC1. Configure the partition to store Active  Directory-integrated zones.