Question: when did the three mile island accident happen
[{'answer': 'March 28 , 1979', 'provenance': [{'wikipedia_id': '105856', 'title': 'Three Mile Island accident', 'start_paragraph_id': 69, 'start_character': 73, 'end_paragraph_id': 69, 'end_character': 88, 'bleu_score': 1.0, 'section': 'Section::::Mitigation policies.:Comparison to U.S. Navy operations.\n'}]}, {'provenance': [{'wikipedia_id': '105856', 'title': 'Three Mile Island accident', 'start_paragraph_id': 1, 'start_character': 57, 'end_paragraph_id': 1, 'end_character': 450, 'bleu_score': 0.6736108756011351, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17653647530162631293}, 'section': 'Section::::Abstract.'}]}]