For a high-latency internet connection, the SSL VPN setting that should be adjusted is:
C . SSL VPN dtls-hello-timeout: This setting determines how long the FortiGate will wait for a DTLS hello message from the client. For high-latency connections, increasing this timeout will prevent SSL VPN negotiation failures caused by delays in receiving the DTLS hello message.
The other options are not suitable:
A . SSL VPN idle-timeout: This setting controls the idle time allowed before a session is terminated, which is not relevant to the initial connection establishment.
B . SSL VPN login-timeout: This setting controls the maximum time allowed for a user to log in, but does not affect connection negotiation.
D . SSL VPN session-ttl: This setting controls the total time-to-live for an SSL VPN session but does not directly address issues caused by high latency.
Reference
FortiOS 7.4.1 Administration Guide - SSL VPN Configuration, page 1415.

To resolve the issue of PC3 not being able to access the internet, the administrator needs to adjust the IP pool configuration or the firewall policy. The following two options will fix the connectivity issue:
B . In the IP pool configuration, set the ending IP to 192.2.0.12: The current IP pool range is 192.2.0.10-192.2.0.11, which only provides two IP addresses for network address translation (NAT). To allow PC3 to access the internet, the IP pool should be expanded to include an additional IP address by changing the end of the range to 192.2.0.12.
D . In the IP pool configuration, set type to overload: Instead of using a one-to-one NAT, changing the type to overload will allow multiple internal addresses (such as PC1, PC2, and PC3) to share a single external IP address. This will solve the issue without needing additional public IP addresses.
The other options are not suitable:
A . In the firewall policy configuration, add 10.0.1.3 as an address object in the source field: This option is unnecessary since the firewall policy already allows all addresses from the source (LAN port3).
C . Configure another firewall policy that matches only the address of PC3 as the source, and then place the policy on top of the list: This option is redundant and would not resolve the underlying issue with the IP pool configuration.
Reference
FortiOS 7.4.1 Administration Guide - Configuring Firewall Policies, page 512.
FortiOS 7.4.1 Administration Guide - Configuring NAT with IP Pools, page 518.

By selecting the "Include in every user group" option in the RADIUS configuration, FortiGate automatically includes this RADIUS server as an authentication source for all user groups. This means any user group configured on the FortiGate will authenticate using this RADIUS server, allowing users to authenticate against the server for any group they belong to.

In the current configuration, although "twitter.com" is allowed in the Static URL Filter, the category "Social Networking" is set to "Block" under the FortiGuard Category Based Filter. To resolve the issue, setting the action to "Exempt" in the Static URL Filter for "twitter.com" will bypass the category-based block for this specific URL while still enforcing the block on other social networking sites.

FortiGate uses the SMB protocol to read the event viewer logs from the DCs.
In agentless polling mode, FortiGate directly connects to the Domain Controllers (DCs) using the SMB protocol to read event logs and detect user login events.
FortiGate does not support workstation check.
In agentless polling mode, FortiGate does not perform workstation checks. It relies on polling the event logs from the Domain Controllers to identify user logins.