Question: what are the three sisters in the blue mountains
[{'answer': 'an unusual rock formation', 'provenance': [{'wikipedia_id': '919779', 'title': 'Three Sisters (Australia)', 'start_paragraph_id': 1, 'start_character': 22, 'end_paragraph_id': 1, 'end_character': 47, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '919779', 'title': 'Three Sisters (Australia)', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 342, 'bleu_score': 0.96746874041754, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6130578051037378614}, 'section': 'Section::::Abstract.'}]}]