The best verified answer is C .
The study guide says that when FortiGate is in conserve mode, it activates protection measures to recover memory space:
“System configuration cannot be changed”
“FortiGate skips quarantine actions (including FortiSandbox analysis)”
It also explains that inspection behavior can be reduced while in conserve mode:
“pass (default): All new sessions pass without inspection until FortiGate switches back to non-conserve mode.”
“The av-failopen setting also applies to flow-based antivirus inspection.”
The FortiOS administration guide summarizes this behavior as:
“This causes functions such as antivirus scanning to change how they operate to reduce the functionality and conserve memory without compromising security.”
That is why C is the closest correct choice: FortiGate can reduce functionality of some processes, especially antivirus-related inspection, to preserve memory.
Why the other options are wrong:
A is wrong because FortiGate does not automatically reboot as a default conserve-mode action. A reboot can be configured through an automation stitch , but that is an optional administrator-defined response, not the built-in conserve-mode behavior
B is wrong because the documentation does not say FortiGate switches from proxy-based inspection to flow-based inspection. Instead, it may pass traffic without inspection depending on av-failopen settings
D is not generally correct for conserve mode . The study guide says FortiGate starts dropping new sessions only when memory usage exceeds the extreme threshold : “If memory usage exceeds the extreme threshold, all new sessions that require inspection (flow-based or proxy-based) are blocked.”
So the verified answer is: C .
