Question: who sang the song unchained melody in the movie ghost
[{'answer': 'The Righteous Brothers', 'provenance': [{'wikipedia_id': '359664', 'title': 'Unchained Melody', 'start_paragraph_id': 3, 'start_character': 261, 'end_paragraph_id': 3, 'end_character': 283, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '359664', 'title': 'Unchained Melody', 'start_paragraph_id': 18, 'start_character': 0, 'end_paragraph_id': 18, 'end_character': 830, 'bleu_score': 0.92314312478239, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 2791111185286369564}, 'section': 'Section::::The Righteous Brothers versions.:Re-recording and re-release.\n'}]}]