Definition: In this task, you will be presented with a passage and have to answer a question based on your understanding of the events inferred from the passage. Try to find the best answer that is most likely to fill in "_". Note that the URLs in the text have been replaced with [Link].
Input: (CNN) In October 2007, the Gallup polling organization wrote that, "Gallup's 2007 national presidential polling strongly points to [Hillary] Clinton winning the 2008 Democratic nomination. Barring something unusual or otherwise unexpected, she is well positioned for the 2008 Democratic primaries." Gallup was wrong. In June 2008, it wrote, "After winning one of the most competitive nomination battles in U.S. history, Barack Obama faces what looks to be an equally tough general election for the presidency." Gallup's polling had Obama and John McCain neck and neck, with McCain leading by a marginal point. In November 2008, Barack Obama was elected president, winning 52.9% of the popular vote to McCain's 45.7%.Sally Kohn: Polls that show Trump closing gap with Clinton alarm some on left, encourage Sanders and supportersNot so fast, she says. Polls at this stage called it wrong about Obama, McCain, Clinton in earlier racesKohn: It's early in horse race; Sanders has right to stay in race 'til California, possibly convention, but should change tone 
 Question:If _ beats Clinton in California, it will elevate him significantly and raise serious questions about Clinton's viability this late in the game.

Sanders