Best Mapping Route

Aside From Mapping An Overland Route Through The Louisiana Territory What Other Outcome Did The Lewis & Clark Expedition Have?

A. Led To The Marbury V. Madison Decision, Which Upheld That A President Does Not Have To Consult Congress When Buying Land
B. Established An American Presence In The Pacific Northwest.
C. Caused Great Britain To Renounce Its Claims In The Western U.S.
D. Produced A Series Of Treaties With Native Americans Allowing U.S. To Take Possession Of Lands Within The Louisiana Territory
E. I'm Not Sure.