Question: who does the voice for anna in frozen
[{'answer': 'Kristen Bell', 'provenance': [{'wikipedia_id': '39696639', 'title': 'Anna (Frozen)', 'start_paragraph_id': 1, 'start_character': 144, 'end_paragraph_id': 1, 'end_character': 156, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '39696639', 'title': 'Anna (Frozen)', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 362, 'bleu_score': 0.9262685672663881, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6359601806579865680}, 'section': 'Section::::Abstract.'}]}]