First off, stop using colours and big fonts. They're supposed to get people's attention for something important, not nuisances.
Now, to answer your question (I am assuming you mean classic with original). Classic is a version of Minecraft that is no longer being developed. It features a very basic lightning system, no entities and no inventory system at all. It's basically minecraft for the cheap people. Minecraft beta was the version of minecraft after alpha, which came after infdev, which came after indev, which came after what we call classic nowadays (Yes, confusing
). Beta however is also no longer being developed as the game has since been released. If you want to know more about what an alpha and beta version mean you can go to this page on wikipedia called
Software release life cycle.