Distributions, Versions, etc.

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.

Kali, Parrot, Ubuntu, Mint, are all based on Debian Linux, and virtual box will detect all as debian, its only used to give a typical value for disk size and ram use, cpu core number etc. just leave it as laterst 64 bit debian and install Kali. You can change the name etc to Kali if it bothers you, it will still work.