Answer:
The answer would be c.) Robert M. La Follette. I hope this helps you.
(B) A fort was established and many were killed by disease.
After Lewis and Clark's expedition, the people of mandan village were faced by a devastating outbreak of smallpox disease in the year 1837, as much as the epidemic was devastating it played an important role in uniting the surviving people in Mandan and Hidatsa village who later interacted in trade farming and hunting