Question: what is the name of america capital city
[{'answer': 'Washington , D.C.', 'provenance': [{'wikipedia_id': '255627', 'title': 'List of capitals in the United States', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 20, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '255627', 'title': 'List of capitals in the United States', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 581, 'bleu_score': 0.866453117696614, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17044557608914890278}, 'section': 'Section::::Abstract.'}]}]