what is the best testing tool to stress test a website ?

I have a college assignment, I was asked to make a stress test on a website that looks like reddit to get the approximate max amount of people that can be connected to the server at the same time, but I don't know what is the best stress test tool that I can start with and can selenium do that kind of test and I want your opinion about loadNinja if it's good? https://kodi.software/ https://dltutuapp.com/tutuapp-download/