How to remove the Suspend option from Ubuntu Desktop?

Edit the following file with root privileges:

sudo gedit /usr/share/polkit-1/actions/org.freedesktop.login1.policy

search for each of the following
org.freedesktop.login1.suspend
org.freedesktop.login1.suspend-multiple-sessions
org.freedesktop.login1.suspend-ignore-inhibit

For each of the above action ids scroll down change the following from yes or whatever to no:

    <defaults>
         <allow_any>no</allow_any>
         <allow_inactive>no</allow_inactive>
         <allow_active>no</allow_active>
    </defaults>

Save the file and reboot.

Following are the snaps depicting the whole process and before and after Results:

Remove Desktops such as Plasma, Mate etc from Desktop Switcher menu in Ubuntu

Do the following as shown in Screenshot to remove Desktop Enviornment Entry - Plasma from Ubuntu Login Screen's Desktop Enviornment Menu. Lightdm Menu.