They all wait. I would say about 2/3 of the people in the lane are turning right, which is why I like to move aside and let them do their right-on-red thing. It gets them out of the way before the light turns green and decreases my chance of being right-hooked. But once a car comes up that is not turning right, everyone is stuck behind them. That's why I don't move to make room if the person behind me has no blinker on. Once you have one person going straight, everyone else has to sit and wait for green. The road I'm on isn't terribly busy, though, but as a result, the light is longish. I am frequently the first vehicle at the intersection, but, depending on the time of day, there can be quite a line-up behind me when the light does change.

Incidentally, taking the intersection from the other direction, the right/straight lane is a little wider, so if I think someone behind me is going to turn right, I take a more leftward position, closer to the B position, so they can pass me on the right and make their turn.