Question: who was the original lead singer of alice in chains
[{'answer': 'Layne Staley', 'provenance': [{'wikipedia_id': '216774', 'title': 'Layne Staley', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 12, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '216774', 'title': 'Layne Staley', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 434, 'bleu_score': 0.734906975660863, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6290485945765710962}, 'section': 'Section::::Abstract.'}]}]