Question: longest border in the world between two countries
[{'answer': 'Canada -- United States border'}, {'provenance': [{'wikipedia_id': '630260', 'title': 'Canada–United States border', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 794, 'bleu_score': 0.805823344466116, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 13265583293186413802}, 'section': 'Section::::Abstract.'}]}]