Question: who was the secretary of state that signed the papers to buy alaska
[{'answer': 'Seward', 'provenance': [{'wikipedia_id': '81455', 'title': 'William H. Seward', 'start_paragraph_id': 0, 'start_character': 11, 'end_paragraph_id': 0, 'end_character': 17, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '81455', 'title': 'William H. Seward', 'start_paragraph_id': 4, 'start_character': 0, 'end_paragraph_id': 4, 'end_character': 765, 'bleu_score': 0.9047851367036591, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 13270638913546350116}, 'section': 'Section::::Abstract.'}]}]