Which are the three different types of Conserve Mode that can occur on a FortiGate device? (Choose three.)

Proxy conserve mode is activated when memory usage by proxy-related processes (like web proxy) exceeds a specific threshold, potentially affecting services handled by these proxies.

'Operating system' is a general term and not a specific, named conserve mode type within FortiGate's memory management distinctions.

Kernel conserve mode is the most severe stage, indicating extremely low available kernel memory, which can lead to critical system instability and service disruption.

System conserve mode is an intermediate state triggered when the total system memory (including both kernel and user space) crosses a high threshold, indicating significant memory pressure.

'Device' is not a specific type of conserve mode; conserve mode refers to a state the device enters due to resource constraints, not a category of mode.