In what way are SSL VPN and IPSec VPN different?

In what way are SSL VPN and IPSec VPN different?
A . SSL VPN is using HTTPS in addition to IKE, whereas IPSec VPN is clientless
B . SSL VPN adds an extra VPN header to the packet, IPSec VPN does not
C . IPSec VPN does not support two factor authentication, SSL VPN does support this
D . IPSec VPN uses an additional virtual adapter; SSL VPN uses the client network adapter only.

Answer: D