Which VPN tunneling protocol should you use?

You support tablets that run Windows 8 Pro. You are designing a remote access server
(RAS) that will be placed behind a firewall. The firewall will accept incoming TCP
connections to ports 80 and 443 only.
You want to connect to the RAS server from a tablet.
You need to create a virtual private network (VPN) connection to the RAS server.
Which VPN tunneling protocol should you use?

A.
IPSec/L2TP

B.
SSTP

C.
PPTP

D.
IPSec/IKEv2