Rih or Bey, whichever releases their lead single first imo.

Beyoncé could easily get a top 10 if she released something generic and actually promoted her singles.. like more than 1 or 2 times.

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Rihanna >> Bey >>> Gaga

Bey has just a good of a chance as Rih or Katy tbh, because Bey's albums sells just as much as theirs in the 10s, considering their last albums sells. Sadly Xtina doesn't have a chance.

Christina most definitely has a chance.. don't count her out.

She has an amazing and distinctive voice.. with the right song she can score a huge hit.

Considering Rihanna is the only one of the three to have a solo top 10 hit this decade then I'd have to say her.

Rihanna, I think.

Rih and Bey will probably both get top tens with their next single release