Which of the following was false about the Lewis and Clark expedition?

Which of the following was false about the Lewis and Clark expedition?
 
  A) Jefferson sent Lewis and Clark out to strengthen U.S. claims to the West.
  B) Lewis and Clark were to search for a Northwest Passage and bring back descriptions of unknown species of plants and animals.
  C) The Corps of Discovery engaged in a series of armed conflicts with Native Americans at nearly every stop along their entire route.
  D) Sacagawea helped guide the party up the Missouri River and through the Rockies.
  E) The group brought back amazingly detailed descriptions of the lands, plants, and animals that they encountered.