Who were promised numerous times by the u. s. government that if they signed a new treaty and moved west once more, they'd be left alone?

These were the Southern Indians. Many including the Cherokee and Shawnee were either threatened or forced off the land.  This event is known as the Indian Removal Act. This led to the Trail of Tears.

the correct answer is:

b) a rich merchant.

abraham lincoln  (february 12, 1809  – april 15, 1865) was an american statesman, politician, and lawyer who served as the 16th  president of the united states  from 1861 until  his assassination  in april 1865. lincoln led the nation through the  american civil war, its bloodiest war and its greatest moral, constitutional, and political crisis.[2][3]  he preserved the  union,  abolished slavery, strengthened the  federal government, and modernized  the u.s. economy.