Question: when did oklahoma become part of the united states
[{'answer': 'November 16 , 1907', 'provenance': [{'wikipedia_id': '22489', 'title': 'Oklahoma', 'start_paragraph_id': 44, 'start_character': 535, 'end_paragraph_id': 44, 'end_character': 553, 'bleu_score': 1.0, 'section': 'Section::::History.:20th and 21st centuries.\n'}]}]