Final answer:
The Sand Creek Massacre and the Battle at Wounded Knee are indicative of the U.S. policy to assimilate Native Americans into white American culture, often through violent and coercive means. The correct option is D.
Step-by-step explanation:
The Sand Creek Massacre of 1864 and the Battle at Wounded Knee in 1890 exemplify the U.S. government's policy toward Native Americans, which was to assimilate them into white American culture. This policy was part of a broader strategy that included the use of force to remove Native Americans from their lands, compulsory education in boarding schools aimed at assimilation, and outlawing traditional Native American practices.
The policy reflected a belief in the superiority of white American culture and an attempt to transform Native American life in accordance with white American values relating to land ownership, religion, education, and lifestyle.