The correct answer is D. were weakened or destroyed.
Step-by-step explanation:
Before the arrival of settlers to America, there were multiple Native American tribes and nations in the territory. However, after the arrival of first settlers around the 17th century, many disappeared or reduced due to the conflict between settlers and natives and the diseases brought by Europeans such as chickenpox or measles. Also, remaining tribes moved to the West far from settlers.
Besides this, during the 19th century, settlers that had created permanent settlements in the east began moving to the west for expanding territory, this had a similar negative effect as many Native Ameican nations were displaced and therefore were weakened or destroyed. An example of this is the trail of tears between 1831 and 1850 in which Native American nations such as the Choctaw and the Cherokee were weakened due to forced displacement.