Your network contains an Active Directory domain named contoso.com. The domain contains a
server named Server1 that runs Windows Server 2012 R2.
You enable and configure Routing and Remote Access (RRAS) on Server1.
You create a user account named User1.
You need to ensure that User1 can establish VPN connections to Server1.
What should you do?

A.
Modify the members of the Remote Management Users group.

B.
Add a RADIUS client.

C.
Modify the Dial-in setting of User1.

D.
Create a connection request policy.

Explanation:
Access permission is also granted or denied based on the dial-in properties of each user account.
http://technet.microsoft.com/en-us/library/cc772123.aspx