Question: The Unanswered Question is a ballet made from work by a man who was regarded as what?
Sentence (from "The Unanswered Question (ballet)"): Other works to the music of Ives in the City Ballet repertory include Peter Martins' "Calcium Light Night", Jerome Robbins' "Ives, Songs" and George Balanchine's "Ivesiana".
Relevant evidence: No