Either A or C would work, so I think you should combine them: declare 30k a victory, and then, if you have something else that is tickling your brain, and that you think you might make 20k words on, give it a start. The 'rules' are a starting point anyway. in more than one year, i've bent them: written on something i'd already started, written a bunch of different things, yadda. The point is just to get writing!