Which two actions should you perform?

Your company has a single Active Directory Domain Services (AD DS) domain named contoso.com that uses Active DirectoryCintegrated DNS. You deploy the Key Management Service (KMS) on a Windows 7 computer. You need to ensure that Windows 7 client computers can locate the KMS host and perform activation. Which two actions should you perform? (Each correct answer presents part of the solution.
Choose two.)

A.
Create and deploy a GPO firewall rule to allow RPC traffic through TCP port 1688 on the client computers.

B.
Deploy a Windows Server 2008 KMS host.

C.
Grant the KMS server the Full Control permission on the _vlmcs._tcp.contoso.com DNS record.

D.
Grant the KMS server the Full Control permission on the _msdcs._tcp.contoso.com DNS zone.