Question: who came up with the law of diminishing marginal utility
[{'answer': 'Carl Menger', 'provenance': [{'wikipedia_id': '23014670', 'title': 'Marginal utility', 'start_paragraph_id': 63, 'start_character': 0, 'end_paragraph_id': 63, 'end_character': 11, 'bleu_score': 1.0, 'section': 'Section::::History.:Marginal Revolution.\n'}]}, {'provenance': [{'wikipedia_id': '23014670', 'title': 'Marginal utility', 'start_paragraph_id': 63, 'start_character': 0, 'end_paragraph_id': 63, 'end_character': 854, 'bleu_score': 0.9844346099707091, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 13662030970906049284}, 'section': 'Section::::History.:Marginal Revolution.\n'}]}]