Question: who was the doctor who identified the cause of the 1854 colera outbreak in england
[{'answer': 'John Snow', 'provenance': [{'wikipedia_id': '17056077', 'title': '1854 Broad Street cholera outbreak', 'start_paragraph_id': 1, 'start_character': 368, 'end_paragraph_id': 1, 'end_character': 377, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '17056077', 'title': '1854 Broad Street cholera outbreak', 'start_paragraph_id': 1, 'start_character': 4, 'end_paragraph_id': 1, 'end_character': 966, 'bleu_score': 0.7591422447720021, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 3241581991013673645}, 'section': 'Section::::Abstract.'}]}]