Final answer:
The correct command to display Syslog server settings for APs on a WLC is typically not listed directly in user options; it requires accessing the settings through the WLC's GUI or specific CLI commands.
Step-by-step explanation:
The student's question relates to displaying Syslog server settings for access points (APs) that are connected to a Wireless LAN Controller (WLC) using the Graphical User Interface (GUI) command. The correct command to display the Syslog server settings on Cisco wireless LAN controllers for all the APs joined to the WLC is not listed among the options provided by the student. Usually, this setting can be found under specific menus in the WLC's GUI, or you can use CLI commands to view the Syslog settings. However, if we are to choose the closest match from the given options, option A (Show syslog) might be the probable command, yet this typically shows the Syslog settings of the WLC itself, not for each individual AP.
One would need to review the documentation specific to the model and version of the WLC being used for the precise command. If accessing via the command-line interface (CLI), you may find a command along the lines of 'show ap config general ' or a similar variant to display Syslog settings for a specific AP.