Which Automatic Start Action should be enabled so that a VM starts with the host if it was running when the Hyper-V service stopped?

The option indicating to "automatically start if it was running when the service stopped" is the correct choice because it ensures that the virtual machine (VM) resumes operation only if it was actively running at the time the Hyper-V service was halted. This behavior is particularly useful in scenarios where a VM should not start unless it was operational before the service interruption, thereby maintaining the intended state of that VM upon the host's reboot or service restart.

This option helps avoid situations where a VM might start in an unintended state (like powered off or paused), which could lead to data inconsistency or operational issues if the VM were to restart without properly shutting down its previous state. By enabling this setting, administrators can ensure a seamless experience and maintain the reliability and integrity of the VMs in their environment.

In contrast, the other options would not appropriately manage the VM's state in relation to the Hyper-V host. For example, starting always with the host could lead to unintended consequences, such as starting VMs that were previously shut down.