Question: who was heading indian army during bangladesh libration war 1971
[{'answer': 'Sam Manekshaw', 'provenance': [{'wikipedia_id': '672766', 'title': 'Bangladesh Liberation War', 'start_paragraph_id': 75, 'start_character': 472, 'end_paragraph_id': 75, 'end_character': 485, 'bleu_score': 1.0, 'section': 'Section::::Surrender and aftermath.\n'}]}, {'provenance': [{'wikipedia_id': '672766', 'title': 'Bangladesh Liberation War', 'start_paragraph_id': 75, 'start_character': 0, 'end_paragraph_id': 75, 'end_character': 1825, 'bleu_score': 0.9678436079706951, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 3749273452915106823}, 'section': 'Section::::Surrender and aftermath.\n'}]}]