Your network contains an Active Directory domain named contoso.com. All domain controllers run Windows Server 2008 R2. One of the domain controllers is named DC1. The network contains a member server named Server1 that runs Windows Server 2012 R2. You need to promote Server1 to a domain controller by using install from media (IFM). What should you do first?
A. Run the Active Directory Domain Services Installation Wizard on DC1.
B. Upgrade DC1 to Windows Server 2012 R2.
C. Run the Active Directory Domain Services Configuration Wizard on Server1.
D. Create a system state backup of DC1.
E. Create IFM media on DC1.