Question: nutrient agar is an example of what medium
[{'answer': 'general purpose medium', 'provenance': [{'wikipedia_id': '19146762', 'title': 'Nutrient agar', 'start_paragraph_id': 1, 'start_character': 19, 'end_paragraph_id': 1, 'end_character': 41, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '19146762', 'title': 'Nutrient agar', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 139, 'bleu_score': 0.7848518349390631, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17932711941346827059}, 'section': 'Section::::Abstract.'}]}]