Question: who said the proletarians have nothing to lose but their chains
[{'answer': 'Karl Marx', 'provenance': [{'wikipedia_id': '43349760', 'title': 'Workers of the world, unite!', 'start_paragraph_id': 1, 'start_character': 134, 'end_paragraph_id': 1, 'end_character': 143, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'Friedrich Engels', 'provenance': [{'wikipedia_id': '43349760', 'title': 'Workers of the world, unite!', 'start_paragraph_id': 1, 'start_character': 148, 'end_paragraph_id': 1, 'end_character': 164, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '43349760', 'title': 'Workers of the world, unite!', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 566, 'bleu_score': 0.8775683656214851, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 4165734024844631542}, 'section': 'Section::::Abstract.'}]}]