Hard to choose, since I hate the dress.
I like Mariah's shoes, but true to form, she manages to make the dress look incredibly vulgar. She's busting out of the top and you can see her underwear - both unnecessary.
Posh looks off somehow. Maybe it would've looked better on her in the black, because she looks very washed out in that color.
The third woman looks okay, and probably the best out of the three, imo. I don't like her shoes, though.