Question: who played bass for crosby stills nash and young
[{'answer': 'Greg Reeves', 'provenance': [{'wikipedia_id': '22192163', 'title': 'Greg Reeves', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 11, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '22192163', 'title': 'Greg Reeves', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 126, 'bleu_score': 0.9146912192286941, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5679050444749399304}, 'section': 'Section::::Abstract.'}]}]