Final answer:
To set the hostname of a switch to asu_switch, one must enter global configuration mode and use the command 'hostname asu_switch'. User mode by itself does not allow changing the hostname.
Step-by-step explanation:
The command syntax to configure the hostname of a switch to asu_switch when you are in user mode is not directly possible. To configure the hostname of a Cisco switch, you must first access global configuration mode.
This is done from user mode by entering the enable command to switch to privileged mode and then typing configure terminal or conf t to access global configuration mode. Once in global configuration mode, the correct command to set the hostname would be:
hostname asu_switch
The options provided all contain elements that are not part of the command itself. The correct option for setting the hostname in global configuration mode is simply hostname followed by the desired hostname, in this case, asu_switch.
Therefore,