I vote for Christina, she deffo has the best chance. I'm almost sure Justin's gonna flop unless he comes up with something new. Britney...well...it depends on the single. She isn't such a hitmachine anymore as she used to be.
I voted for Christina. I think either Christina or Justing have the best chance. J.Lo won't get to one. She'll be lucky to make it in the top 10. Britney, it all depends on the single. If she get's back to normal she has a chance.
Britney has messed up her chances by marrying the Federjerk. Her image was very important. Now, to get to #1, Britney will have to have a quality song (another toxic would do it for her.. but those are hard to come by).