Question: what are the oldest baseball stadiums in the united states
[{'answer': 'Fenway Park', 'provenance': [{'wikipedia_id': '643381', 'title': 'List of current Major League Baseball stadiums', 'start_paragraph_id': 2, 'start_character': 151, 'end_paragraph_id': 2, 'end_character': 162, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'Wrigley Field', 'provenance': [{'wikipedia_id': '643381', 'title': 'List of current Major League Baseball stadiums', 'start_paragraph_id': 3, 'start_character': 182, 'end_paragraph_id': 3, 'end_character': 195, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]