The correct answer is D) the Dawes Severalty Act.
The policy that required American Indians to maintain the land they were given in exchange for receiving American citizenship and ownership of the land after 25 years was the Dawes Severalty Act.
This act authorized the President of the United States to break up Native American Indian lands and form individual plots. To become citizens of the United States, the American Indians had to accept this decision. The aim of the Dawes Severalty Act was to introduce the Native American people into the modern American society and leaving behind its culture and traditions. So the policy that required American Indians to maintain the land they were given in exchange for receiving American citizenship and ownership of the land after 25 years was the Dawes Severalty Act.
