Question: where do the tigris and euphrates rivers begin
[{'answer': 'the mountains of eastern Anatolia', 'provenance': [{'wikipedia_id': '209798', 'title': 'Tigris–Euphrates river system', 'start_paragraph_id': 2, 'start_character': 40, 'end_paragraph_id': 2, 'end_character': 73, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '209798', 'title': 'Tigris–Euphrates river system', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 369, 'bleu_score': 0.9694566079002921, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 13629925568214497360}, 'section': 'Section::::Abstract.'}]}]