How to close "sirincservice" in MacOS Big Sur

I need to take an online test, I'm told I need to close all applications before starting. Once all applications have been closed I run the system test but there is an error saying I need to close "sirincservice" application. I have turned off Siri in System Settings and done a retest but it says the application is still open. I am unable to complete the test with this open, does anyone know what this application is and how to close it?

[Re-Titled by Moderator]