Question: what key is mirrors by justin timberlake in
[{'answer': 'E ♭ major', 'provenance': [{'wikipedia_id': '38453763', 'title': 'Mirrors (Justin Timberlake song)', 'start_paragraph_id': 10, 'start_character': 147, 'end_paragraph_id': 10, 'end_character': 154, 'bleu_score': 1.0, 'section': 'Section::::Composition and lyrical interpretation.\n'}]}, {'provenance': [{'wikipedia_id': '38453763', 'title': 'Mirrors (Justin Timberlake song)', 'start_paragraph_id': 10, 'start_character': 0, 'end_paragraph_id': 10, 'end_character': 690, 'bleu_score': 0.9625181433061291, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10502638228805509351}, 'section': 'Section::::Composition and lyrical interpretation.\n'}]}]