qnli question: Along with Trey Songz, Patti LaBelle, Toni Braxton, Whitney Houston, Aretha Franklin, Frank Ocean, Craig David and Mariah Carey, who is a well-known urban AC artist? sentence: Urban AC's core artists include Luther Vandross, Trey Songz, Patti LaBelle, Toni Braxton, Whitney Houston, Aretha Franklin, Frank Ocean, Craig David and Mariah Carey.