Question: who is the original lead singer for ac dc
[{'answer': 'Dennis Laughlin', 'provenance': [{'wikipedia_id': '149225', 'title': 'AC/DC', 'start_paragraph_id': 11, 'start_character': 629, 'end_paragraph_id': 11, 'end_character': 644, 'bleu_score': 1.0, 'section': 'Section::::History.:Early years.\n'}]}, {'provenance': [{'wikipedia_id': '149225', 'title': 'AC/DC', 'start_paragraph_id': 11, 'start_character': 414, 'end_paragraph_id': 11, 'end_character': 857, 'bleu_score': 0.581712233413285, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 7267382259611926796}, 'section': 'Section::::History.:Early years.\n'}]}]