Question: who challenged jimmy carter for the democratic nomination for president in 1980
[{'answer': 'Ted Kennedy', 'provenance': [{'wikipedia_id': '14713051', 'title': '1980 Democratic Party presidential primaries', 'start_paragraph_id': 2, 'start_character': 51, 'end_paragraph_id': 2, 'end_character': 62, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'Jerry Brown', 'provenance': [{'wikipedia_id': '14713051', 'title': '1980 Democratic Party presidential primaries', 'start_paragraph_id': 20, 'start_character': 12, 'end_paragraph_id': 20, 'end_character': 23, 'bleu_score': 1.0, 'section': 'Section::::The candidates.:Popular vote.\n'}]}]