Which Cisco UCS firmware reboot policy must be used in the maintenance policy to prevent the server firmware from upgrading automatically and wait for user input before proceeding?

A scheduled reboot policy typically specifies a future time for the reboot to occur, which would still be an automatic action at that designated time without waiting for explicit user input for the reboot itself.

A timer-automatic reboot policy initiates a reboot after a configured delay without requiring explicit user intervention, which contradicts the requirement to wait for user input.

An immediate reboot policy causes the server to reboot as soon as the firmware upgrade process completes, without waiting for any user input.

The user-ack reboot policy requires explicit user acknowledgment from the Cisco UCS Manager GUI or CLI before the server reboots to complete a firmware upgrade. This ensures that the upgrade process waits for manual intervention, preventing automatic reboots.