Question: when did the virgin islands become a us territory
[{'answer': '1916', 'provenance': [{'wikipedia_id': '32135', 'title': 'United States Virgin Islands', 'start_paragraph_id': 19, 'start_character': 58, 'end_paragraph_id': 19, 'end_character': 62, 'bleu_score': 1.0, 'section': 'Section::::History.:Danish period.\n'}]}]