Question: when did east pakistan separate from west pakistan
[{'answer': '1971', 'provenance': [{'wikipedia_id': '17902675', 'title': 'History of East Pakistan', 'start_paragraph_id': 1, 'start_character': 58, 'end_paragraph_id': 1, 'end_character': 62, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '17902675', 'title': 'History of East Pakistan', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 228, 'bleu_score': 0.950578622812921, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14367652982584251277}, 'section': 'Section::::Abstract.'}]}]