It's more pragmatic and logistically cleaner once implemented, but it might be even less likely than (B). (C) would require realigning every existing Power 5 conference and creating 3 new ones. It also would inevitably prompt an antitrust lawsuit (from the "Group of 5" conference members left out of the big playoff) that would have legal merit.
(B) is unlikely too, but it wouldn't entail the same antitrust issues and wouldn't be as difficult to implement. It only would require the consent of the poached schools, not a majority of 64 schools.