MZ, sorry for the late reply. I am in Texas (just got up), don't know where you are at, so perhaps the time difference caught us. I now understand your issue, thanks for your picture even if fuzzy, I can see enough to understand. No need to apologize, I may not be so old but learning can be slow for anyone as technology gets more complicated by the day.
Regarding your request, I am not aware of any option to just remove one computer while keeping others (I don't use iTunes Wi-Fi sync). You could try clicking on the > on the computers you want to remove (right side of your screenshot above) and see if it presents you the option. If not you can remove all of them by doing a settings reset as per below and then going back in and resetting your phone including iTunes Wi-Fi sync for the computers you do want on the list. This will not remove any data, apps, mail, etc. currently on your phone but will reset the settings which would take a few minutes to reconfigure.
Go to Settings > General > Reset > Reset All Settings. Let the phone restart, connect to your wireless, activate the device and set all your settings. You will then have the option to plug the iPhone into the computer you want to sync with (you should sync to one computer only as having more than one will present new issues of their own). To do this connect to the one computer, and click on "Sync with this iPhone over Wi-Fi".
If you have further questions do not hesitate to ask. I would appreciate your feedback whether the above worked ok for you or not.
Regards,
elcpu
BTW, for future reference, to take a screen shot of the current view on your iPhone just press the Home and Sleep button just for a second or so and then release. A screenshot will be taken and it will appear in Photos under Camera Roll. Try it....