It depends on your computer hardware really.
If you're on windows, go to start, hit run, and type in msinfo32.
This will bring up system information, under the first page that comes up, you should see a line called processor. That will give you your processor model and family. Chances are, you want this one. Since intel HD graphics are the most common.
OpenCL driver for Intel® Iris™ and HD Graphics for Windows (64-bit and 32-bit)