This treaty was to bring peace between the whites and the Sioux who agreed to settle within the Black Hills reservation in the Dakota Territory. This occured in 1868 so the answer would be:
THIS IS THE CORRECT ANSWER:
A.) That they would not be forced to move to a reservation.
The Black Hills were already a sacred land to the Sioux people from when they arrived in the 18th century and drove out the other tribes, who moved west. They claimed the land, which they called Ȟe Sápa (Black Mountains). The mountains commonly became known as the Black Hills. HOWEVER years later in 1874, General George A. Custer led an expedition into the Black Hills accompanied by miners who were seeking gold. So the answer could be confused to be:
THIS IS THE EASILY MISTAKEN ANSWER:
D.) That they had the rights to any gold found in their territory.
But that was never true. Once the government found out about the potential income, they kind of pushed the Sioux out of the way (like they always did) to obtain that wealth. Disputes over the land still exist today.