I want to know the answer to the following question:
Who have hot AC format radio stations had to change the music they play?
All the background I'm provided with is that "Part of the reason why more and more hot AC stations are forced to change is that less and less new music fits their bill; most new rock is too alternative for mainstream radio and most new pop is now influenced heavily by dance-pop and electronic dance music.". Is that enough to answer the question?