Question: who is the winner of 2015 royal rumble
[{'answer': 'Roman Reigns', 'provenance': [{'wikipedia_id': '40486196', 'title': 'Royal Rumble (2015)', 'start_paragraph_id': 2, 'start_character': 98, 'end_paragraph_id': 2, 'end_character': 110, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '40486196', 'title': 'Royal Rumble (2015)', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 492, 'bleu_score': 0.9458134147569861, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6492254841875776855}, 'section': 'Section::::Abstract.'}]}]