Question: who sang grease is the word in the movie
[{'answer': 'Frankie Valli', 'provenance': [{'wikipedia_id': '9324701', 'title': 'Grease (song)', 'start_paragraph_id': 1, 'start_character': 58, 'end_paragraph_id': 1, 'end_character': 71, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '9324701', 'title': 'Grease (song)', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 341, 'bleu_score': 0.9679895851501501, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 18042146200084696876}, 'section': 'Section::::Abstract.'}]}]