Question: who authorized the construction of the boulder dam
[{'answer': 'President Coolidge', 'provenance': [{'wikipedia_id': '14308', 'title': 'Hoover Dam', 'start_paragraph_id': 13, 'start_character': 22, 'end_paragraph_id': 13, 'end_character': 40, 'bleu_score': 1.0, 'section': 'Section::::Background.:Planning and agreements.\n'}]}, {'provenance': [{'wikipedia_id': '14308', 'title': 'Hoover Dam', 'start_paragraph_id': 13, 'start_character': 0, 'end_paragraph_id': 13, 'end_character': 485, 'bleu_score': 0.976327165973018, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 12855605667005784029}, 'section': 'Section::::Background.:Planning and agreements.\n'}]}]