Which of the following IPsec configuration modes can be used for implementing L2TP- over- IPSec VPNs?
A. Policy-based IPsec only.
B. Route-based IPsec only.
C. Both policy-based and route-based VPN.
D. L2TP-over-IPSec is not supported by FortiGate devices.
D for 6.0
C
For 5.2 A is OK
For 5.4 C is OK: “L2TP over IPsec is supported on the FortiGate unit for both policy-based and route-based configurations”
https://help.fortinet.com/fos50hlp/54/Content/FortiOS/fortigate-ipsecvpn-54/L2TP_and_IPsec/Config_Overview.htm
you are wrong
https://cookbook.fortinet.com/l2tp-ipsec-vpn-on-fortigate/
This recipe assumes that the FortiGate unit is operating in NAT/Route mode and that it has a static public IP address. This recipe is designed as a policy-based IPsec VPN, not route-based.
C