Question: who is the national leader who is called the iron man of india
[{'answer': 'Sardar Vallabhbhai Patel', 'provenance': [{'wikipedia_id': '59659', 'title': 'Vallabhbhai Patel', 'start_paragraph_id': 67, 'start_character': 213, 'end_paragraph_id': 67, 'end_character': 237, 'bleu_score': 1.0, 'section': 'Section::::Legacy.\n'}]}, {'provenance': [{'wikipedia_id': '59659', 'title': 'Vallabhbhai Patel', 'start_paragraph_id': 74, 'start_character': 0, 'end_paragraph_id': 74, 'end_character': 724, 'bleu_score': 0.9628278278632151, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 784000202655147657}, 'section': 'Section::::Legacy.:Rashtriya Ekta Diwas.\n'}]}]