The copy running-config startup-config command is used to save the running configuration to NVRAM. This command will should always been run after making changes to the configuration. Failure to do so will result in the changes being discarded at the next restart of the router. When the router is restarted, the startup configuration file is copied to RAM and becomes the running configuration.

The copy startup-config running-config command is incorrect because this command is used to copy the startup configuration to the running configuration. The command would be used to discard changes to the configuration without restarting the router.

The move startup-config running-config and move startup-config running-config commands are incorrect because these are not valid Cisco IOS commands. There is no move command when discussing the manipulation of configuration files.