In Order to Ensure No One Uses Public Computer Terminals

Multiple Choice

In order to ensure no one uses public computer terminals after 5 pm,you've set the log on hours for the guest user accounts to deny log on after 5.However,you've noticed that users are still using the terminals after 5 pm,while other users are denied the ability to log in.
Why are some users denied to log on,while other users are still using the terminals?

A) Logon hours can only be set on stand-alone computers
B) The users were logged on prior to 5pm
C) You highlighted 8 am to 5 pm,but selected "Logon denied"
D) The machines the other users are on have pending update installs that are preventing the log off sequence from taking place