D because I’ve had this question in my class
Actually, the civil war make their relationship became much worse.
Because of the civil war, the ally has to lose a lot of resources for war supplies and equipment. This led to a situation where the allies no longer able to pay the treaties that they promisd to pay to the Sioux, which eventually ended up in conflict between the two group.
Answer:
exploration
Explanation:exploring is to dicover for instance Cristopher colombus set out to explore or discover.