Q:Unearthed is an acclaimed box set by Johnny Cash released two months after his death in 2003. It was produced by Rick Rubin and released by American Recordings. The first three discs feature outtakes and alternate versions of songs recorded for American Recordings Unchained American III: Solitary Man and American IV: The Man Comes Around. The fourth disc My Mother's Hymn Book features gospel songs Cash first learned from his mother as a child. Given a list of categories: company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work, what category does the paragraph belong to?
A:
Album