You need to ensure that remote users can connect to the file servers

Your network is connected to the Internet through a firewall.
Remote users connect to Microsoft Windows SharePoint Services (WSS) located on the internal network by using HTTPS.
Users require access to file servers located on the internal network.

You need to ensure that remote users can connect to the file servers.
The solution must not require that any additional TCP ports be opened on the firewall.

What should you do?

A.
Implement a PPTP virtual private network (VPN) solution.

B.
Implement an L2TP virtual private network (VPN) solution.

C.
Implement a Terminal Services Web Access (TS Web Access) solution.

D.
Implement a Secure Socket Tunneling Protocol (SSTP) virtual private network (VPN) solution.