Question: who sang lead vocals on hold the line
[{'answer': 'Bobby Kimball', 'provenance': [{'wikipedia_id': '9216378', 'title': 'Hold the Line', 'start_paragraph_id': 1, 'start_character': 156, 'end_paragraph_id': 1, 'end_character': 169, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '9216378', 'title': 'Hold the Line', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 437, 'bleu_score': 0.9346183847893801, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 1988343487441919188}, 'section': 'Section::::Abstract.'}]}]