What is DP?

Option select is when you input a command and it can possibly have 2 different out comes depending on what your opponent does.

So TJ had one where you could press down up LP/LK at the same time and if they jumped you would get a Light tremor to recapture them in the air…if they didnt jump you would get a throw.

Something along those lines. I know there is a popular one with RYU that gives you either a DP or a Round house kick. You can search Daigo SF option select and may get a better answer.