Question: what type of metamorphic rock is formed from limestone
[{'answer': 'marble', 'provenance': [{'wikipedia_id': '44424', 'title': 'Metamorphic rock', 'start_paragraph_id': 3, 'start_character': 54, 'end_paragraph_id': 3, 'end_character': 60, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '44424', 'title': 'Metamorphic rock', 'start_paragraph_id': 7, 'start_character': 0, 'end_paragraph_id': 7, 'end_character': 725, 'bleu_score': 0.9813933169956551, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5019204565853508792}, 'section': 'Section::::Metamorphic minerals.\n'}]}]