Your network contains a server named Server1 that runs Windows Server 2008 R2. Server1 has the Remote Access Service role service installed. Server1 is configured as a VPN server.You need to ensure that you can configure Server1 as a Network Address Translation (NAT) server.What should you do first on Server1？（）

• A、Enable IPv4 routing.
• B、Enable IPv6 routing.
• C、Add a new routing protocol.
• D、Add the Routing role service.