Question: where does the mouth of the mississippi river start
[{'answer': 'Gulf of Mexico', 'provenance': [{'wikipedia_id': '19579', 'title': 'Mississippi River', 'start_paragraph_id': 1, 'start_character': 303, 'end_paragraph_id': 1, 'end_character': 317, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '19579', 'title': 'Mississippi River', 'start_paragraph_id': 28, 'start_character': 0, 'end_paragraph_id': 28, 'end_character': 577, 'bleu_score': 0.7709238988005611, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10407960261467024658}, 'section': 'Section::::Divisions.:Lower Mississippi.\n'}]}]