'X Factor': What exactly is Rock & Roll?

The theme of the night on "The X Factor" was theoretically all about Rock & Roll. But when it came down to song selection and execution, the interpretations of this concept seemed to be all over the map.

At numerous points during the evening, the judges seemed confused as to what constitutes the genre, sparking a number of arguments. But to be honest, we weren't sure ourselves. R.E.M is certainly a rock band, but is "Everybody Hurts" a rock song?

So perhaps you Zappers can help us out with this. Which performance was really in the true spirit of the evening?

Vote below and make your opinion known.