question: Which recording artist released its fourth studio album, titled Ether, which featured a guest appearance from singer, songwriter and rapper CeeLo Green?
answer: B.o.B.
context: Title: Trouble Man: Heavy Is the Head
  Passage: Trouble Man: Heavy Is the Head is the eighth studio album by American hip hop recording artist T.I..  It was released on December 18, 2012, by Grand Hustle Records and Atlantic Records.  The production has provided by some of T.I.'s longtime collaborators; including DJ Toomp, Jazze Pha, Pharrell Williams and Lil' C.  These high-profile record producers such as T-Minus, Cardiak, No I.D., Rico Love, Planet VI, Tommy Brown and Chuck Diesel, also contributed to the album.  The album features guest appearances from P!nk, Lil Wayne, André 3000, R. Kelly, Akon, Meek Mill, CeeLo Green, ASAP Rocky, Trae tha Truth, Victoria Monet and Grand Hustle's own D.O.P.E.
  Title: Ether (B.o.B album)
  Passage: Ether is the fourth studio album by American hip hop recording artist B.o.B.  Issued on May 12, 2017, by Label No Genre, Grand Hustle Records and Empire Distribution, it is the first album by B.o.B to be released independently.  The album is the fifth installment in his "Element" series going back to 2015, with the previous four compiled on 2016's "Elements".  The album features guest appearances from Lil Wayne, Young Thug, T.I., Big K.R.I.T., Ty Dolla Sign, Usher, CeeLo Green, Young Dro, and more.
  Title: CeeLo Green
  Passage: Thomas DeCarlo Callaway (born May 30, 1975), better known by his stage name CeeLo Green (sometimes rendered as Cee Lo Green), is an American singer, songwriter, rapper, record producer and actor.
  Title: Heart Blanche
  Passage: Heart Blanche is the fifth studio album by American recording artist CeeLo Green.  The album was released on November 6, 2015, by Atlantic Records.
citations: Ether (B.o.B album) CeeLo Green