Question: which celebrity has the most twitter followers 2018
[{'answer': 'Katy Perry', 'provenance': [{'wikipedia_id': '52247588', 'title': 'List of most-followed Twitter accounts', 'start_paragraph_id': 1, 'start_character': 135, 'end_paragraph_id': 1, 'end_character': 145, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]