Question: who is associated with the discovery of oxygen
[{'answer': 'Carl Wilhelm Scheele', 'provenance': [{'wikipedia_id': '22303', 'title': 'Oxygen', 'start_paragraph_id': 3, 'start_character': 133, 'end_paragraph_id': 3, 'end_character': 153, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]