Question: who is the no. 1 ranked tennis player in the world
[{'answer': 'Rafael Nadal', 'provenance': [{'wikipedia_id': '2575118', 'title': 'List of ATP number 1 ranked singles tennis players', 'start_paragraph_id': 9, 'start_character': 0, 'end_paragraph_id': 9, 'end_character': 12, 'bleu_score': 1.0, 'section': 'Section::::Records and particularities.\n'}]}, {'provenance': [{'wikipedia_id': '2575118', 'title': 'List of ATP number 1 ranked singles tennis players', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 123, 'bleu_score': 0.864196187778114, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10881541027131602108}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '2575118', 'title': 'List of ATP number 1 ranked singles tennis players', 'section': 'Section::::Records and particularities.\n', 'start_paragraph_id': 9, 'end_paragraph_id': 9, 'meta': {'evidence_span': ['Rafael Nadal has the longest timespan, 9 years, between his first and last year-end No. 1 titles', 'Rafael Nadal has the longest timespan, 9 years, between his first and last year-end No. 1 titles, 2008 and 2017', 'Rafael Nadal has the longest timespan, 9 years, between his first and last year-end No. 1 titles, 2008 and 2017']}}]}]