Question: who won women's singles us open 2017
[{'answer': 'Sloane Stephens', 'provenance': [{'wikipedia_id': '54683068', 'title': "2017 US Open – Women's Singles", 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 15, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '54683068', 'title': "2017 US Open – Women's Singles", 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 413, 'bleu_score': 0.806458095317608, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 9840847404455569219}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '51884449', 'title': '2017 US Open (tennis)', 'section': 'Section::::Tournament.\n', 'start_paragraph_id': 5, 'end_paragraph_id': 5, 'meta': {'evidence_span': ["The men's singles tournament concluded with Rafael Nadal defeating Kevin Anderson in the final, while the women's singles tournament concluded with Sloane Stephens defeating Madison Keys in the final.", "due to a knee injury that ended his season, while Kerber lost in the first round to Naomi Osaka. The men's singles tournament concluded with Rafael Nadal defeating Kevin Anderson in the final, while the women's singles tournament concluded with Sloane Stephens defeating Madison Keys in the final. The 2017 US Open was the 137th edition of the tournament and took place at the USTA Billie Jean King National Tennis Center in Flushing MeadowsCorona Park of Queens in New York City, New York, United States. The tournament was held on 14 DecoTurf hard courts.", 'concluded with Sloane Stephens defeating Madison Keys in the final']}}]}, {'provenance': [{'wikipedia_id': '54683068', 'title': "2017 US Open  Women's Singles", 'section': 'Section::::Abstract.', 'start_paragraph_id': 1, 'end_paragraph_id': 1, 'meta': {'evidence_span': ["Sloane Stephens won her first Grand Slam title, defeating Madison Keys in the final, 63, 60, to win the Women's Singles tennis title at the 2017 US Open.", "Sloane Stephens won her first Grand Slam title, defeating Madison Keys in the final, 63, 60, to win the Women's Singles tennis title at the 2017 US Open. It was the first all-American women's final at the US Open since 2002, and the second time in three years that the final featured two first-time Grand Slam singles finalists from the same country. Stephens became the second unseeded woman in the Open Era to win the US Open after Kim Clijsters in 2009.", "Sloane Stephens won her first Grand Slam title, defeating Madison Keys in the final, 63, 60, to win the Women's Singles tennis title at the 2017 US Open."]}}]}]