Question: when does the nba pre season start 2017
[{'answer': 'September 30', 'provenance': [{'wikipedia_id': '53555999', 'title': '2017–18 NBA season', 'start_paragraph_id': 32, 'start_character': 23, 'end_paragraph_id': 32, 'end_character': 35, 'bleu_score': 1.0, 'section': 'Section::::Preseason.\n'}]}, {'provenance': [{'wikipedia_id': '53555999', 'title': '2017–18 NBA season', 'start_paragraph_id': 32, 'start_character': 0, 'end_paragraph_id': 32, 'end_character': 59, 'bleu_score': 0.8242367502646051, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17810223462401440553}, 'section': 'Section::::Preseason.\n'}]}]