Question: what is the most expensive brand of caviar
[{'answer': 'Beluga caviar', 'provenance': [{'wikipedia_id': '1253375', 'title': 'Beluga caviar', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 13, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '1253375', 'title': 'Beluga caviar', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 474, 'bleu_score': 0.889484845929798, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 4115739696977628990}, 'section': 'Section::::Abstract.'}]}]