Creating a new OS with VirtualBox:

I select the Kali Linux ISO image from the drop-down box and VirtualBox auto detects Linux and Ubuntu 64. I thought Kali and Ubuntu were 2 different Linux OSs? And why does Kali run when Ubuntu 64 is chosen or Debian 64 or Debian 11 Bullseye?... There's a huge list of versions to choose from and so far everything has worked (some good, some bad). Why isn't Kali on that list? Where does Kali come in and what should I be running it on? I'm so confused.