Question: when did myrtle beach air force base close
[{'answer': '31 March 1993', 'provenance': [{'wikipedia_id': '50356325', 'title': 'Myrtle Beach Air Force Base', 'start_paragraph_id': 12, 'start_character': 16, 'end_paragraph_id': 12, 'end_character': 29, 'bleu_score': 1.0, 'section': 'Section::::Closing.\n'}]}, {'provenance': [{'wikipedia_id': '50356325', 'title': 'Myrtle Beach Air Force Base', 'start_paragraph_id': 12, 'start_character': 0, 'end_paragraph_id': 12, 'end_character': 29, 'bleu_score': 0.6803749333171201, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 15546397915443334950}, 'section': 'Section::::Closing.\n'}]}]