Love the backless on D, but the empire waist is unflattering unless the wearer is very slender in the hips. You have some good shape down there and it will make your waistline look higher and your overall shape will look more pear like. You have blue/green eyes, right? The color of A will bring that out beautifully. C is pretty sexy, but I like subtle-sexy elegance at holiday (excepting new year's eve) parties over the more overt looks, though I'm certain you're look hot as hell in it.