Your company has an Active Directory domain. You log on to the domain controller. The Active Directory Schema snap-in is not available in the Microsoft Management Console （MMC）. You need to access the Active Directory Schema snap-in. What should you do（）
- ARegister Schmmgmt.dll.
- BLog off and log on again by using an account that is a member of the Schema Administrators group.
- CUse the Ntdsutil.exe command to connect to the Schema Master operations master and open the schema for writing.
- DAdd the Active Directory Lightweight Directory Services （AD LDS） role to the domain controller by using Server Manager.