Question: when does the big ten basketball tournament start
[{'answer': 'February 28', 'provenance': [{'wikipedia_id': '53379348', 'title': "2018 Big Ten Conference Men's Basketball Tournament", 'start_paragraph_id': 1, 'start_character': 203, 'end_paragraph_id': 1, 'end_character': 214, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '53379348', 'title': "2018 Big Ten Conference Men's Basketball Tournament", 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 455, 'bleu_score': 0.9321992460304711, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 3210711568214752572}, 'section': 'Section::::Abstract.'}]}]