Question: who sings vocals on bridge over troubled water
[{'answer': 'Garfunkel', 'provenance': [{'wikipedia_id': '634661', 'title': 'Bridge over Troubled Water (song)', 'start_paragraph_id': 1, 'start_character': 69, 'end_paragraph_id': 1, 'end_character': 78, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '634661', 'title': 'Bridge over Troubled Water (song)', 'start_paragraph_id': 9, 'start_character': 0, 'end_paragraph_id': 9, 'end_character': 125, 'bleu_score': 0.9067110266941041, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10065377110785339802}, 'section': 'Section::::Background.\n'}]}]