which of the following editions of Windows Server 2008 R2 can you upgrade the domain controllers?

You work as a Server Administrator for company Inc. The company has a Windows Server 2003 R2
network environment. You need to upgrade the network environment to Windows Server 2008 R2.
The network includes domain controllers running Windows Server 2003 R2 Enterprise Edition. To
which of the following editions of Windows Server 2008 R2 can you upgrade the domain controllers?
Each correct answer represents a complete solution. Choose two.

A.
Windows Server 2008 R2 Standard

B.
Windows Server 2008 R2 Datacenter

C.
Windows Server 2008 R2 Enterprise

D.
Windows Server 2008 R2 Foundation

Explanation:
You can upgrade the domain controllers running Windows Server 2003 R2 Enterprise Edition to the
Windows Server 2008 R2 Enterprise or Windows Server 2008 R2 Datacenter edition.
2003 R2 Enterprise Edition to the Windows Server 2008 R2 Foundation or Windows Server 2008 R2
Standard edition.