Question: which type of storage technology is used in pen drives
[{'answer': 'flash memory', 'provenance': [{'wikipedia_id': '400414', 'title': 'USB flash drive', 'start_paragraph_id': 1, 'start_character': 57, 'end_paragraph_id': 1, 'end_character': 69, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '400414', 'title': 'USB flash drive', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 755, 'bleu_score': 0.61632047656398, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 1814573586556957165}, 'section': 'Section::::Abstract.'}]}]