Your company has a main office and a branch office. The branch office contains a read-only domain controller named RODC1. You need to ensure that a user named Admin1 can install updates on RODC1. The solution must prevent Admin1 from logging on to other domain controllers. What should you do（）
- ARun ntdsutil.exe and use the Roles option.
- BRun dsmgmt.exe and use the Local Roles option.
- CFrom Active Directory Sites and Services， modify the NTDS Site Settings.
- DFrom Active Directory Users and Computers， add the user to the Server Operators group.