Question: the indus basin treaty was signed in karachi by
[{'answer': 'President of Pakistan Ayub Khan', 'provenance': [{'wikipedia_id': '3603967', 'title': 'Indus Waters Treaty', 'start_paragraph_id': 1, 'start_character': 329, 'end_paragraph_id': 1, 'end_character': 360, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'Prime Minister of India Pandit Jawaharlal Nehru'}, {'provenance': [{'wikipedia_id': '3603967', 'title': 'Indus Waters Treaty', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 360, 'bleu_score': 0.5388504429516261, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16928798114211000744}, 'section': 'Section::::Abstract.'}]}]