According to a theory embraced by some contemporary musicians, music is simply a series of sounds, bereft of meaning. But these musicians, because they understand that their theory is radically nonconformist, encourage audience acceptance by prefacing their performances with explanations of their intentions. Thus, even their own music fails to conform to their theory. Which one of the following, if assumed, enables the argument's conclusion to be properly drawn? ['Music that opposes current popular conceptions of music is less likely to be enjoyed by audiences than is music that accords with such conceptions.', 'Musicians whose music has no meaning do not preface their performances with explanations of their intentions.', 'The fact that music is distinguishable from a random series of sounds only when it has meaning makes music with meaning more appealing to audiences than music without meaning.', 'The human ability to think symbolically and to invest anything with meaning makes it very difficult to create music that has no meaning.']