Question: from which country do most visitors to canada originate
[{'answer': 'United States', 'provenance': [{'wikipedia_id': '288026', 'title': 'Tourism in Canada', 'start_paragraph_id': 232, 'start_character': 567, 'end_paragraph_id': 232, 'end_character': 580, 'bleu_score': 1.0, 'section': "Section::::Canada's provinces and territories.:Newfoundland and Labrador.\n"}]}]