Question: name the delta formed by ganga and brahmaputra
[{'answer': 'Ganges - Brahmaputra Delta', 'provenance': [{'wikipedia_id': '1064742', 'title': 'Ganges Delta', 'start_paragraph_id': 1, 'start_character': 4, 'end_paragraph_id': 1, 'end_character': 30, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '1064742', 'title': 'Ganges Delta', 'start_paragraph_id': 1, 'start_character': 4, 'end_paragraph_id': 1, 'end_character': 552, 'bleu_score': 0.7485394995506921, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 1635534055839402837}, 'section': 'Section::::Abstract.'}]}]