Question: who has the biggest aircraft carrier in the world
[{'answer': 'United States', 'provenance': [{'wikipedia_id': '2219', 'title': 'Aircraft carrier', 'start_paragraph_id': 2, 'start_character': 580, 'end_paragraph_id': 2, 'end_character': 593, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]