"Alright, so I feel like a scrub for having to ask, but does someone want to explain to me what exactly an option select is? I have sort of an idea (like if you hold db and hit lp+lk during block stun, you'll tech if they stop in the middle of a block string and try to throw, right?), but I've seen it mentioned in several places yet haven't been able to find a clear explanation of the theory behind it."
An option select is when you do a single maneuver that, depending on what happens, does different things. Your d/b+throw example is one, but you have what it does wrong. What it actually does is, if they try to throw you will tech, *but* if they don't, you will do a crouching lk.
Another one is a Makoto one that Ken I said on Gootecks' podcast. In certain situations he'll do a super jump (tap down, then up), then do a 3/4 circle from up to back. In this case, if someone were to throw out a low attack like crouching lk/mk/whatever, it would parry the low attack and then immediately do her command grab. If they *didn't* attack, he would super jump then do her EX axe kick slightly above the ground.
