It will be aweful if it's not Gaga. I mean, 2 years of recreating her image and building hype is already too long just to have ARTPOP numbers in the end. But nevertheless, she has the lowest recent album/single numbers among others, so topping ARTPOP will already be a hit and easy for her. But I just don't see her slaying hard next year just like her first 2 eras. A PRISM-kind if success will be good for her.
EDIT: I just read, there's Brit in the choices, but she's already a legend, so it doesn't matter. smh.
Probably Rih. Everyone's forgotten about the false starts to the era and are thirsty for new Rihanna!
Gaga's having a good year, so she's another possibility. And now that Britney's become a popular Instagram star, she's poised for a comeback! She just needs the right lead single.