Question: one of the gershwin's greatest hits was his composition for piano and orchestra known as
[{'answer': 'Rhapsody in Blue', 'provenance': [{'wikipedia_id': '13066', 'title': 'George Gershwin', 'start_paragraph_id': 1, 'start_character': 245, 'end_paragraph_id': 1, 'end_character': 261, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '13066', 'title': 'George Gershwin', 'start_paragraph_id': 21, 'start_character': 0, 'end_paragraph_id': 21, 'end_character': 251, 'bleu_score': 0.890257934258152, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 18141852502237080612}, 'section': 'Section::::Biography.:Musical, Europe and classical music, 1924–1928.\n'}]}]