Which type of VPN is based on the concept of trusted group members using the GDOI key management protocol?

Which type of VPN is based on the concept of trusted group members using the GDOI
key management protocol?

A.
DMVPN

B.
SSLVPN

C.
GETVPN

D.
EzVPN

E.
MPLS VPN

F.
FlexVPN