Which protocol is used by FortiGate to synchronize session tables in an HA cluster?

The FortiGate Cluster Protocol (FGCP) is used to synchronize session tables, configuration, and state information between HA cluster members to ensure seamless failover. VRRP (B) is for router redundancy, OSPF (C) and BGP (D) are routing protocols, not used for HA synchronization. Exact extract: "FGCP synchronizes session tables, configurations, and state information between FortiGate HA cluster members to ensure continuity during failover."