Question: when did hot springs become a national park
[{'answer': '1921', 'provenance': [{'wikipedia_id': '19187901', 'title': 'History of the National Park Service', 'start_paragraph_id': 16, 'start_character': 435, 'end_paragraph_id': 16, 'end_character': 439, 'bleu_score': 1.0, 'section': 'Section::::Beginnings.:Mineral Springs line, 1832–1916.\n'}]}, {'provenance': [{'wikipedia_id': '19187901', 'title': 'History of the National Park Service', 'start_paragraph_id': 16, 'start_character': 0, 'end_paragraph_id': 16, 'end_character': 547, 'bleu_score': 0.978138775770484, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8840980564776043674}, 'section': 'Section::::Beginnings.:Mineral Springs line, 1832–1916.\n'}]}]