Question: who sang mary's boy child in 1957
[{'answer': 'Harry Belafonte', 'provenance': [{'wikipedia_id': '2913060', 'title': "Mary's Boy Child", 'start_paragraph_id': 5, 'start_character': 0, 'end_paragraph_id': 5, 'end_character': 15, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}, {'provenance': [{'wikipedia_id': '2913060', 'title': "Mary's Boy Child", 'start_paragraph_id': 5, 'start_character': 0, 'end_paragraph_id': 5, 'end_character': 542, 'bleu_score': 0.9276281369144621, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17538234912835705059}, 'section': 'Section::::History.\n'}]}]