Question: when did prison break season 4 come out
[{'answer': 'September 1 , 2008', 'provenance': [{'wikipedia_id': '19929970', 'title': 'Prison Break (season 4)', 'start_paragraph_id': 1, 'start_character': 121, 'end_paragraph_id': 1, 'end_character': 139, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]