You need to test the remote access security solutions. To this end in the test environment in the Chicago office, you install an IAS server on TestRAS1. After RADIUS clients have been configured appropriately, users in the test environment who attempt to connect via TestVPN1 are not authenticated. You need to address this issue for deployment to the production network. You thus need to ensure that all Testdomain user accounts are authenticated using the IAS on TestRAS1.
What should you do?

A.
Upgrade TestRAS1 to domain controller.

B.
Upgrade both TestRAS1 and TestVPN1 to domain controllers.

C.
Add TestRAS1 to the RAS and IAS Servers group in Active Directory.

D.
Add TestRAS1 and TestVPN1 to the RAS and IAS Servers group in Active Directory.