Oh my god! You are far above my level, I would like to suggest something, yet I don't realy know that I would notice something that you would not... Your thumbnails, colors and gestures are just glorious!
As for the illustration, I personaly feel like B captures her as a mistress of demonic creatures, raveling in her power. C looks like she is a warrior/chieften/warmonger type (as for me it doesn't quite cut it). Tho I think I like A as well, she looks like she is in the middle of a battlefield ready to command her demonic creatures.
I would recomend you to realy think about somehow mixing A and B, that would capture her "mistress" vibe together with battleground situation.
Can I get some critiques and suggestions from you on my own work? I am perfectionist, so I am afraid to do something by myself rly (I'm rookie in graphic art atm, but I plan to grow bigger skill asap.)
I can't wait to see finished illustration, meanwhile I will continue working on my own project.
Keep it cool!