Your network contains a server named Server1 that runs Windows Server 2008 R2 Service Pack (SP1).
All users have laptops that run Windows 7. The users frequently work from network locations that only allow outbound communication to the Internet by using HTTP and HTTPS.
You plan to configure Server1 as a VPN server.
You need to identify which VPN protocol you should use to ensure that all of the users can establish VPN connections to Server1. Which VPN protocol should you identify?
A. PPTP
B. SSTP
C. L2TP
D. IKEv2
