How Did Indians Assist the Expedition of Lewis and Clark

How did Indians assist the expedition of Lewis and Clark?

A) Indians tricked Lewis and Clark into believing they were lost when they were not in order to protect their land.
B) Indians agreed not to harm the expedition members in exchange for weapons.
C) Indians lived throughout the territory and provided food, shelter, and navigation assistance.
D) Indians did not challenge the authority of the expedition leaders even when they made bad decisions.