Question: who sings the opening song for sons of anarchy
[{'answer': 'Curtis Stigers', 'provenance': [{'wikipedia_id': '27214589', 'title': 'This Life (song)', 'start_paragraph_id': 1, 'start_character': 107, 'end_paragraph_id': 1, 'end_character': 121, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '27214589', 'title': 'This Life (song)', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 573, 'bleu_score': 0.9792717993254391, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 807616344320587537}, 'section': 'Section::::Background.\n'}]}]