On the site, they pegged a governor of Oregon for B, forget his name, but he fit everything perfectly.
Bellwether state is one that almost always votes for the winner of the presidential election. The three bellwether states are Ohio, Missouri and New Mexico. So, three was a governor of [possibly] one of those three states. Virginia and Florida are also becoming bellwethers. This person also has never been a VP or presidential candidate.
Then C probably is Mark Sanford.