Question: which country has won most davis cups in tennis
[{'answer': 'United States', 'provenance': [{'wikipedia_id': '9659006', 'title': 'List of Davis Cup champions', 'start_paragraph_id': 1, 'start_character': 301, 'end_paragraph_id': 1, 'end_character': 314, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '9659006', 'title': 'List of Davis Cup champions', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 401, 'bleu_score': 0.7165666219749951, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 12074642596818105754}, 'section': 'Section::::Abstract.'}]}]