Question: when did jennifer lopez released her first single
[{'answer': 'May 1999', 'provenance': [{'wikipedia_id': '16175', 'title': 'Jennifer Lopez', 'start_paragraph_id': 15, 'start_character': 60, 'end_paragraph_id': 15, 'end_character': 68, 'bleu_score': 1.0, 'section': 'Section::::Career.:1997–1999: Breakthrough with "Selena" and "On the 6".\n'}]}, {'provenance': [{'wikipedia_id': '16175', 'title': 'Jennifer Lopez', 'start_paragraph_id': 15, 'start_character': 0, 'end_paragraph_id': 15, 'end_character': 1280, 'bleu_score': 0.991360488753344, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17671455991862649659}, 'section': 'Section::::Career.:1997–1999: Breakthrough with "Selena" and "On the 6".\n'}]}]