Question: who won the battle of iwo jima ww2
[{'answer': 'United States', 'provenance': [{'wikipedia_id': '60027', 'title': 'Battle of Iwo Jima', 'start_paragraph_id': 1, 'start_character': 85, 'end_paragraph_id': 1, 'end_character': 98, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '60027', 'title': 'Battle of Iwo Jima', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 617, 'bleu_score': 0.940455544020087, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6384520922122485389}, 'section': 'Section::::Abstract.'}]}]