Question: who's the main actor in sling blade
[{'answer': 'Billy Bob Thornton', 'provenance': [{'wikipedia_id': '171522', 'title': 'Sling Blade', 'start_paragraph_id': 1, 'start_character': 66, 'end_paragraph_id': 1, 'end_character': 84, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]