Question: which successful white blues vocalist was the lead singer for big brother and the holding company
[{'answer': 'Janis Joplin', 'provenance': [{'wikipedia_id': '610704', 'title': 'Big Brother and the Holding Company', 'start_paragraph_id': 1, 'start_character': 276, 'end_paragraph_id': 1, 'end_character': 288, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '610704', 'title': 'Big Brother and the Holding Company', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 637, 'bleu_score': 0.95005935086738, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 18390689471837561366}, 'section': 'Section::::Abstract.'}]}]