Question: where is the mekong river delta located in vietnam
[{'answer': 'southwestern Vietnam', 'provenance': [{'wikipedia_id': '518534', 'title': 'Mekong Delta', 'start_paragraph_id': 1, 'start_character': 165, 'end_paragraph_id': 1, 'end_character': 185, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]