Question: when did the south declare war on the north
[{'answer': 'April 1861', 'provenance': [{'wikipedia_id': '863', 'title': 'American Civil War', 'start_paragraph_id': 1, 'start_character': 359, 'end_paragraph_id': 1, 'end_character': 369, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]