Final answer:
Lewis and Clark distributed peace medallions with Thomas Jefferson's image on them as a tool of diplomacy to Native American leaders.
Step-by-step explanation:
One of the major tools of diplomacy that Lewis and Clark distributed to American Indian leaders they encountered was C) peace medallions with Thomas Jefferson's image on them. These medallions served as tokens of friendship and goodwill between the explorers and the Native American tribes. By offering these medallions, Lewis and Clark aimed to establish positive relations and gain the cooperation and support of the Native American leaders along their journey.
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