Question: which team won the ncaa mens basketball championship in april 2015
[{'answer': 'Duke Blue Devils', 'provenance': [{'wikipedia_id': '45410510', 'title': "2015 NCAA Division I Men's Basketball Championship Game", 'start_paragraph_id': 4, 'start_character': 200, 'end_paragraph_id': 4, 'end_character': 216, 'bleu_score': 1.0, 'section': 'Section::::Overview.\n'}]}]