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（）

A. Run ntdsutil.exe and use the Roles option.
B. Run dsmgmt.exe and use the Local Roles option.
C. From Active Directory Sites and Services， modify the NTDS Site Settings.
D. From Active Directory Users and Computers， add the user to the Server Operators group.