Katy Perry and Carly Rae Jepsen are going head to head in Round 2 of March Music Madness! During Round 1, Perry's anthemic 'Firework' beat out Miley Cyrus' 'Wrecking Ball' with 61% of the votes. It was a closer call for Carly Rae Jepsen's 'Call Me Maybe,' which just barely won over One Direction's 'What Makes You Beautiful' -- but ultimately Jepsen edged 1D out of the competition with slightly more than 55% percent of the votes. Now, 'Firework' and 'Call Me Maybe' are battling it out! Which pop song could be the Greatest Pop Song of the Modern Era?