The traffic from the user on Local-Client (10.0.1.10) pinging the IP address of Remote-FortiGate (10.200.3.1) will match the firewall policy with the service "PING traffic". According to the firewall policy:
* Policy ID 6 is set for PING traffic and uses the NAT IP pool "SNAT-Remote1", which is defined as
10.200.1.99.

B. FortiGate acts as an HTTP reverse proxy.
When using SSL VPN in web mode, FortiGate acts as an HTTP reverse proxy. It allows users to access internal resources securely via a web browser without the need for a VPN client installation. The FortiGate device receives HTTP requests from the client, forwards them to the internal server, and relays the responses back to the client.
So, the correct answer is
B. FortiGate acts as an HTTP reverse proxy.

From LAN to WAN, the Source NAT will use the IPPOOL with address configured 10.200.1.100 Destination NAT, from WAN to LAN, will use the VIP The question says SNAT, so the only correct answer here (looking at the IP Pool) is D.
(Step 2): FortiGate uses as NAT IP the external IP address defined in the VIP when performing SNAT on all egress traffic sourced from the mapped address in the VIP, provided the matching firewall policy has NAT enabled.
Note that you can override the behavior described in step 2 by using an IP pool.
Reference: https://kb.fortinet.com/kb/documentLink.do?externalID=FD44529

The debug trace output shows that the packet was "Denied by forward policy check (policy 0)." In FortiGate, policy ID 0 corresponds to the default implicit deny policy. This means that if a packet does not match any configured firewall policies, it is denied by the default implicit policy.
References:
* FortiOS 7.4.1 Administration Guide: Firewall Policies