Question: when was the last time oklahoma state won a national championship in football
[{'answer': '1945', 'provenance': [{'wikipedia_id': '7958137', 'title': 'Oklahoma State Cowboys football', 'start_paragraph_id': 6, 'start_character': 111, 'end_paragraph_id': 6, 'end_character': 115, 'bleu_score': 1.0, 'section': 'Section::::History.:Jim Lookabaugh era (1939–1949).\n'}]}]