Question: who are primarily credited with the development of the unix operating system
[{'answer': 'Ken Thompson', 'provenance': [{'wikipedia_id': '21347364', 'title': 'Unix', 'start_paragraph_id': 1, 'start_character': 206, 'end_paragraph_id': 1, 'end_character': 218, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'Dennis Ritchie', 'provenance': [{'wikipedia_id': '21347364', 'title': 'Unix', 'start_paragraph_id': 1, 'start_character': 220, 'end_paragraph_id': 1, 'end_character': 234, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'Brian Kernighan', 'provenance': [{'wikipedia_id': '21347364', 'title': 'Unix', 'start_paragraph_id': 6, 'start_character': 681, 'end_paragraph_id': 6, 'end_character': 696, 'bleu_score': 1.0, 'section': 'Section::::Overview.\n'}]}, {'answer': 'Douglas McIlroy', 'provenance': [{'wikipedia_id': '21347364', 'title': 'Unix', 'start_paragraph_id': 13, 'start_character': 273, 'end_paragraph_id': 13, 'end_character': 288, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}, {'answer': 'Joe Ossanna', 'provenance': [{'wikipedia_id': '21347364', 'title': 'Unix', 'start_paragraph_id': 13, 'start_character': 294, 'end_paragraph_id': 13, 'end_character': 305, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}]