Question: who sang the song big rock candy mountain
[{'answer': 'Harry McClintock', 'provenance': [{'wikipedia_id': '158507', 'title': 'Big Rock Candy Mountain', 'start_paragraph_id': 1, 'start_character': 45, 'end_paragraph_id': 1, 'end_character': 61, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '158507', 'title': 'Big Rock Candy Mountain', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 502, 'bleu_score': 0.9505764710553931, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 9341196028870772873}, 'section': 'Section::::Abstract.'}]}]