Question: where is the youngest rock in the earths crust found
[{'answer': 'at mid-ocean ridges', 'provenance': [{'wikipedia_id': '981252', 'title': 'Oceanic crust', 'start_paragraph_id': 3, 'start_character': 453, 'end_paragraph_id': 3, 'end_character': 472, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '981252', 'title': 'Oceanic crust', 'start_paragraph_id': 13, 'start_character': 0, 'end_paragraph_id': 13, 'end_character': 376, 'bleu_score': 0.9274581800092581, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 9798992886801413400}, 'section': 'Section::::Composition.:Life cycle.\n'}]}]