A FortiClient fails to establish a VPN tunnel with a FortiGate unit. The following information
is displayed in the FortiGate unit logs: Which of the following statements is a possible cause
for the failure to establish the VPN tunnel?

A.
The phase 1 configuration on the FortiGate unit uses Aggressive mode while FortiClient
uses Main mode.

B.
There is a mismatch between the FortiGate unit and the FortiClient IP addresses in the
phase 2 settings.

C.
An IPSec DHCP server is not enabled on the external interface of the FortiGate unit.

D.
There is no IPSec firewall policy configured for the policy-based VPN.