Question: who has won the most concacaf gold cups
[{'answer': 'Mexico', 'provenance': [{'wikipedia_id': '250685', 'title': 'CONCACAF Gold Cup', 'start_paragraph_id': 4, 'start_character': 499, 'end_paragraph_id': 4, 'end_character': 505, 'bleu_score': 1.0, 'section': 'Section::::History.:Championships before CONCACAF.\n'}]}]