You are cruel, very cruel. C will eventually come, once I can wrap my mind around that without Cassandra cringing in horror.
The B for the Lady is up there, under Catwo's comment.
B - Styx
This is something I actually realized the other day - it was quite the epiphany, if I may be so bold. Styx's loyalty has never wavered: it has always been her children, first and foremost. She will make the choice that has the more probability of keeping them safe.
She has a bigger rapport with Acheron than with any other of her river-siblings, and probably than with the other Okeanides, too. They don't talk about it.
She views Hera as a sister, from the time the goddess spent under Tethys and Okeanos's fostering. Of all the Olympians, she is the least likely to suffer directly at Styx's hands, for the sake of the bond they share.