Question: in 1867 the u.s. purchased alaska from the russian empire for approximately how many cents per acre
[{'answer': 'about 2 cents per acre', 'provenance': [{'wikipedia_id': '193703', 'title': 'Alaska Purchase', 'start_paragraph_id': 10, 'start_character': 742, 'end_paragraph_id': 10, 'end_character': 764, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}, {'provenance': [{'wikipedia_id': '193703', 'title': 'Alaska Purchase', 'start_paragraph_id': 10, 'start_character': 0, 'end_paragraph_id': 10, 'end_character': 774, 'bleu_score': 0.781154909052015, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 13508892860067412656}, 'section': 'Section::::History.\n'}]}]