The hostname command is used to assign the router a name for identification. This command is a global configuration mode command. The syntax of the command is as follows:

Router(config)# hostname [name]
The name parameter of the command specifies the new host name for the router.

The description command is incorrect because this command is used to set a description for an interface. The description command is an interface configuration mode command.

The banner motd command is used to specify a message of the day (MOTD) banner to users logging into the router. This is a global configuration mode command, but it does not assign a name to the router for identification.

The banner exec command enables a banner message to be displayed when an EXEC process is created; for example, if a line is activated or an incoming connection is made to a telnet line.