Question: who was the first billionaire in the united states
[{'answer': 'John D. Rockefeller', 'provenance': [{'wikipedia_id': '428105', 'title': 'Billionaire', 'start_paragraph_id': 1, 'start_character': 759, 'end_paragraph_id': 1, 'end_character': 778, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '428105', 'title': 'Billionaire', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 845, 'bleu_score': 0.670746472620351, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 7739072373833360491}, 'section': 'Section::::Abstract.'}]}]