Question: where did immigrants gather to begin their journey westward on the oregon trail
[{'answer': 'Independence , Missouri', 'provenance': [{'wikipedia_id': '48711', 'title': 'Oregon Trail', 'start_paragraph_id': 80, 'start_character': 22, 'end_paragraph_id': 80, 'end_character': 45, 'bleu_score': 1.0, 'section': 'Section::::Routes.:Kansas.\n'}]}, {'provenance': [{'wikipedia_id': '48711', 'title': 'Oregon Trail', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 810, 'bleu_score': 0.9669266300094901, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 4402652013038627374}, 'section': 'Section::::Abstract.'}]}]