Answer:
C. American Indian populations declined in huge numbers.
Step-by-step explanation:
Primarily, native populations greatly declined because of the diseases that were introduced by the Europeans.
Smallpox was extremely deadly and killed half of the native population, and other diseases like malaria and yellow fever were very deadly as well.
Native populations also declined from the abuse they faced from the Europeans. Many were enslaved under abusive working conditions, leading to them dying from starvation or torture.
Lastly, the natives also died from warfare/conflicts with the Europeans.