Question: which tool requires an underlying operating system in order to create and manage virtual machines
[{'answer': 'hypervisor or Virtual Machine Manager'}, {'provenance': [{'wikipedia_id': '18311356', 'title': 'Virtualization', 'start_paragraph_id': 5, 'start_character': 0, 'end_paragraph_id': 5, 'end_character': 419, 'bleu_score': 0.8411423732211321, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14698042545864858561}, 'section': 'Section::::Hardware virtualization.\n'}]}]