It will use the prefered graphics API for your operating system. On Windows it will be the latest version of DirectX your system supports.
Viewing post in RCBasic - BASIC Programming Language for Games comments
RCBasic is a programming language. It has a full graphics library that allows you to implement spritesheets and tilesets if you wish. There are examples that show how to do this already. I have implemented spritesheets and tilesets in the engine I built for the game I am currently working on. You can checkout the source code for that here: n00b Engine