Question: what is the biggest convention center in the us
[{'answer': 'McCormick Place', 'provenance': [{'wikipedia_id': '40224166', 'title': 'List of convention centers in the United States', 'start_paragraph_id': 118, 'start_character': 12, 'end_paragraph_id': 118, 'end_character': 27, 'bleu_score': 1.0, 'section': 'Section::::By state.:Illinois.\n'}]}]