The battle between federal forces and the Oglala Sioux at Little Big Horn in $1876$ was precipitated by the $1874$ :

discovery of gold in the Black Hills and the subsequent flood of white settlers into Sioux land.

a disagreement between Sitting Bull and Lt$.$ Col. George Armstrong Custer over a poker gam$.$

failure of Indian agents to deliver goods to Sioux encamped near the Black Hills.

All the above.