Question: when was the world war 2 memorial built in washington dc
[{'answer': 'September 2001', 'provenance': [{'wikipedia_id': '426008', 'title': 'World War II Memorial', 'start_paragraph_id': 31, 'start_character': 21, 'end_paragraph_id': 31, 'end_character': 35, 'bleu_score': 1.0, 'section': 'Section::::Construction.\n'}]}, {'provenance': [{'wikipedia_id': '426008', 'title': 'World War II Memorial', 'start_paragraph_id': 31, 'start_character': 0, 'end_paragraph_id': 31, 'end_character': 104, 'bleu_score': 0.8702397637697911, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6471093859337234606}, 'section': 'Section::::Construction.\n'}]}]