Question: where is the longest bridge located in africa
[{'answer': 'Cairo', 'provenance': [{'wikipedia_id': '3043808', 'title': 'Third Mainland Bridge', 'start_paragraph_id': 1, 'start_character': 223, 'end_paragraph_id': 1, 'end_character': 228, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '3043808', 'title': 'Third Mainland Bridge', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 397, 'bleu_score': 0.5761156445930621, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 2183155316147971725}, 'section': 'Section::::Abstract.'}]}]