Question: who won the gold cup in cheltenham 2018
[{'answer': 'Native River', 'provenance': [{'wikipedia_id': '56853181', 'title': '2018 Cheltenham Gold Cup', 'start_paragraph_id': 2, 'start_character': 20, 'end_paragraph_id': 2, 'end_character': 32, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '56853181', 'title': '2018 Cheltenham Gold Cup', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 211, 'bleu_score': 0.797608782157286, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8404770443610884694}, 'section': 'Section::::Abstract.'}]}]