Your company has a main office and a branch office. The network contains a single Active Directory domain. The main office contains a domain controller named DC1. You need to install a domain controller in the branch office by using an offline copy of the Active Directory database. What should you do first（）

A. From the Ntdsutil tool， create an IFM media set.
B. From the command prompt， run djoin.exe /loadfile.
C. From Windows Server Backup， perform a system state backup.
D. From Windows PowerShell， run the get-ADDomainController cmdlet.