Based on the system performance output provided, the memory usage on the FortiGate device is at 90%, which is above the green threshold (82%) but below the red threshold (88%). Given this high memory usage, the FortiGate device will enter "conserve mode" to prevent further resource exhaustion. In conserve mode:
B . FortiGate has entered conserve mode: When the memory usage reaches or exceeds certain thresholds (in this case, the green and red thresholds), the FortiGate enters conserve mode to protect itself from running out of memory entirely. This mode limits some functionalities to reduce memory usage and avoid a potential system crash.
D . Administrators can access FortiGate only through the console port: During conserve mode, administrative access might be restricted, and administrators may only be able to connect to the device via the console port. This restriction is in place to ensure that the FortiGate can be managed directly, even under low resource conditions.
The other options are not correct:
A . FortiGate will start sending all files to FortiSandbox for inspection: This is unrelated to memory usage and conserve mode.
C . Administrators cannot change the configuration: While access may be limited, configuration changes can still be made via the console port.
Reference
FortiOS 7.4.1 Administration Guide - Monitoring System Resources and Performance, page 325.
FortiOS 7.4.1 Administration Guide - Conserve Mode, page 330.