Question: what body of water do the tigris and euphrates rivers empty into
[{'answer': 'Persian Gulf', 'provenance': [{'wikipedia_id': '209798', 'title': 'Tigris–Euphrates river system', 'start_paragraph_id': 1, 'start_character': 186, 'end_paragraph_id': 1, 'end_character': 198, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '209798', 'title': 'Tigris–Euphrates river system', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 351, 'bleu_score': 0.87540210596635, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16350874173777420623}, 'section': 'Section::::Abstract.'}]}]