Question: when were voters first invited to participate in the presidential nomination process
[{'answer': '1901', 'provenance': [{'wikipedia_id': '185311', 'title': 'United States presidential primary', 'start_paragraph_id': 9, 'start_character': 493, 'end_paragraph_id': 9, 'end_character': 497, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}, {'provenance': [{'wikipedia_id': '185311', 'title': 'United States presidential primary', 'start_paragraph_id': 9, 'start_character': 0, 'end_paragraph_id': 9, 'end_character': 1045, 'bleu_score': 0.9876155018005031, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 1575068213950215071}, 'section': 'Section::::History.\n'}]}]