Question: when did the articles of confederation became effective
[{'answer': 'March 1 , 1781', 'provenance': [{'wikipedia_id': '691', 'title': 'Articles of Confederation', 'start_paragraph_id': 73, 'start_character': 744, 'end_paragraph_id': 73, 'end_character': 758, 'bleu_score': 1.0, 'section': 'Section::::Signatures.\n'}]}, {'provenance': [{'wikipedia_id': '691', 'title': 'Articles of Confederation', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 701, 'bleu_score': 0.9013859364994441, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 2375814169344308639}, 'section': 'Section::::Abstract.'}]}]