Question: who holds the world record for men's 400m hurdles
[{'answer': 'Kevin Young', 'provenance': [{'wikipedia_id': '707859', 'title': '400 metres hurdles', 'start_paragraph_id': 3, 'start_character': 204, 'end_paragraph_id': 3, 'end_character': 215, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '707859', 'title': '400 metres hurdles', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 399, 'bleu_score': 0.900781798891443, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 13934578454741696243}, 'section': 'Section::::Abstract.'}]}]