The best answer is B) All of the Above.
A) is correct. It is fairly common knowledge that the European United States largely considered the Native Americans to be "savages" and uncivilized.
C) They wanted to relocate them to reservations. In 1851, Congress passed a law to allocate land for Indian reservations. Several similar laws followed.
D) They wanted to treat them as foreign nations. The United States, and other European powers, had the instinct to apply inter-national relations guidelines to the Native Americans, which failed due to the diversity of tribes and the lack of history that the Native Americans had with relations of this kind