Selena's Shirtless Exes WHO'D YOU RATHER?

0730_selena_exes_ratherIt's a showdown of Selena Gomez' prior suitors.

Here's a topless photo that 20-year-old Nick Jonas shared on his social media page (left) -- and an equally skin-filled photo 19-year-old Justin Bieber posted on his (right).

While Selena was linked to both buff beaus... you can only choose one!

The question is...