Question: what city are the sand dunes in colorado
[{'answer': 'Alamosa', 'provenance': [{'wikipedia_id': '465511', 'title': 'Great Sand Dunes National Park and Preserve', 'start_paragraph_id': 4, 'start_character': 561, 'end_paragraph_id': 4, 'end_character': 568, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]