Question: where is the source of river nile found
[{'answer': 'White Nile', 'provenance': [{'wikipedia_id': '21244', 'title': 'Nile', 'start_paragraph_id': 2, 'start_character': 40, 'end_paragraph_id': 2, 'end_character': 50, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]