Question

under the dawes act, the reservation land not allotted to american indians was sold
○ to specific tribes as reservation land.
○ to american indians who wanted more.
○ to white settlers and railroad companies.
○ to tribal chiefs to divide on their own.

Explanation:

The Dawes Act aimed to assimilate Native Americans by allotting individual plots of reservation land. The remaining unallotted land was opened for sale, primarily to white settlers and railroad companies to encourage western expansion and private landownership. The other options are incorrect: it wasn't sold back to tribes as reservation land, nor to individual Indians wanting more (the allotment was for individuals already), and tribal chiefs didn't get it to divide on their own.

Answer:

C. to white settlers and railroad companies