Question: what is at the mouth of the mississippi river
[{'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.'}]}]