The next round.
You can vote for a "song" as opposed to a "recording." So if you love Bad but think the album cut is weak, no matter, you love the song and can vote for it.
I plan to list The Sweetest Thing in the next round though you could argue it should be here. I'm not listing b sides unless they are released in some bigger way, like Silver and Gold had a live take on R&H, 11OTT was on UABRS, and Sweetest Thing had a single release.
Edit: Not that 11OTT was a b side but anyway.