Your network contains a stand-alone root certification authority （CA）. You have a server named Server1 that runs Windows Server 2008 R2. You issue a server certificate to Server1. You deploy Secure Socket Tunneling Protocol （SSTP） on Server1. You need to recommend a solution that allows external partner computers to access internalnetwork resources by using SSTP. What should you recommend？（）

A. Enable Network Access Protection （NAP） on the network.
B. Deploy the Root CA certificate to the external computers.
C. Implement the Remote Desktop Connection Broker role service.
D. Configure the firewall to allow inbound traffic on TCP Port 1723.