Question: who is credited with devising the three-age system
[{'answer': 'C.J. Thomsen', 'provenance': [{'wikipedia_id': '31295', 'title': 'Three-age system', 'start_paragraph_id': 110, 'start_character': 379, 'end_paragraph_id': 110, 'end_character': 391, 'bleu_score': 1.0, 'section': 'Section::::Bronze Age subdivisions.\n'}]}, {'provenance': [{'wikipedia_id': '31295', 'title': 'Three-age system', 'start_paragraph_id': 1, 'start_character': 4, 'end_paragraph_id': 1, 'end_character': 709, 'bleu_score': 0.925051135427533, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 11541277773614773104}, 'section': 'Section::::Abstract.'}]}]