Question: who plays elena in vampire diaries season 8
[{'answer': 'Nina Dobrev', 'provenance': [{'wikipedia_id': '8900348', 'title': 'Nina Dobrev', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 11, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]