The following videos are intensely difficult to follow due to the speed at which they move. That said, if you look at the reading materials meant to go along with these, you stand to learn a lot about what an Option Select technique actually is, how and why it works, and why it is important to a high level game. Here is a blurb from the author, 3nigmat1c;
An option-select is used to create a situation where you can nullify the effective options of your opponent to a 50/50 guess, force them to only take a single option or put themselves in an unfavorable situation. The most well-known option-selects are offensive option-selects, such as buffers. There are also defensive option-selects like crouch-techs and option-select blocks, which can be used while under pressure or to generally return the match to neutral.