Question: who sang lead vocals on black magic woman
[{'answer': 'Gregg Rolie', 'provenance': [{'wikipedia_id': '5992063', 'title': 'Black Magic Woman', 'start_paragraph_id': 2, 'start_character': 48, 'end_paragraph_id': 2, 'end_character': 59, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]