Question: when does ben stone leave law and order
[{'answer': 'the end of season four', 'provenance': [{'wikipedia_id': '1840876', 'title': 'Benjamin Stone (Law & Order character)', 'start_paragraph_id': 1, 'start_character': 201, 'end_paragraph_id': 1, 'end_character': 223, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '1840876', 'title': 'Benjamin Stone (Law & Order character)', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 251, 'bleu_score': 0.8928756684056031, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 3389930590427895177}, 'section': 'Section::::Abstract.'}]}]