Question: what metal is on top of the washington monument
[{'answer': 'aluminum', 'provenance': [{'wikipedia_id': '167585', 'title': 'Washington Monument', 'start_paragraph_id': 3, 'start_character': 404, 'end_paragraph_id': 3, 'end_character': 412, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '167585', 'title': 'Washington Monument', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 920, 'bleu_score': 0.703571502113977, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 9292199626658054556}, 'section': 'Section::::Abstract.'}]}]