Question: who sings the song i am iron man
[{'answer': 'Black Sabbath', 'provenance': [{'wikipedia_id': '1299122', 'title': 'Iron Man (song)', 'start_paragraph_id': 1, 'start_character': 75, 'end_paragraph_id': 1, 'end_character': 88, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]