Metamorphosis is the fourth studio album by Iron Butterfly released in 1970. Though it was not as successful as its predecessor Ball (1969) it reached number 16 on the US charts. The album was recorded as a trio; Erik Brann who left because of band disputes was replaced by four session guitarists. Two of them Mike Pinera and Larry Rhino Reinhardt (called El Rhino on the sleeve) would become members of Iron Butterfly shortly after the album's release. 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?
The answer to this question is:
Album