Question: who sang let it go in frozen movie
[{'answer': 'Queen Elsa', 'provenance': [{'wikipedia_id': '41245530', 'title': 'Let It Go (Disney song)', 'start_paragraph_id': 1, 'start_character': 322, 'end_paragraph_id': 1, 'end_character': 332, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '41245530', 'title': 'Let It Go (Disney song)', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 599, 'bleu_score': 0.9806740509884301, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 15115080232191385553}, 'section': 'Section::::Abstract.'}]}]