Question: how long is the nile river in miles and kilometers
[{'answer': '6,853 km'}, {'answer': '4,258 miles'}, {'provenance': [{'wikipedia_id': '21244', 'title': 'Nile', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 599, 'bleu_score': 0.569166429446322, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17659027785623321317}, 'section': 'Section::::Abstract.'}]}]