Question: who made the first journey by citizens of the united states
[{'answer': 'Meriwether Lewis', 'provenance': [{'wikipedia_id': '17615', 'title': 'Lewis and Clark Expedition', 'start_paragraph_id': 1, 'start_character': 440, 'end_paragraph_id': 1, 'end_character': 456, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'William Clark', 'provenance': [{'wikipedia_id': '17615', 'title': 'Lewis and Clark Expedition', 'start_paragraph_id': 1, 'start_character': 496, 'end_paragraph_id': 1, 'end_character': 509, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '17615', 'title': 'Lewis and Clark Expedition', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 509, 'bleu_score': 0.9218493128353921, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8851374679846032388}, 'section': 'Section::::Abstract.'}]}]