What must you configure to enable ADVPN?

Refer to the exhibit.

What must you configure to enable ADVPN?
A . On the hub VPN, only the device needs additional phase one sett
B . ADVPN should only be enabled on unmanaged FortiGate devices.
C . Each VPN device has a unique pre-shared key configured separately on phase one
D . The protected subnets should be set to address object to all (0.0 .0. o/o).

Answer: C