The Sioux and Sitting Bull led the attack on General George Armstrong Custer's cavalry at the Battle of Little Big Horn. Why did the Sioux take this course of action?
A) General Custer wanted Congress to outlaw the Sioux's ritual Ghost Dance.
B) The Transcontinental Railroad was moving through the area the Sioux inhabited.
C) The U.S. Army was threatening to take over the Sioux's gold mines, which were key to the Native American economy.
D) The U.S. Government had broken promises to let the Sioux remain in the Black Hills and was attempting to force them from those lands.

The correct answer is D) The US Government had broken promises to let the Sioux remain in the Black Hills and was attemptint to force them from those lands.

The Battle of Little Bighorn (aka Custer's Last Stand) was a military engagement between the Sioux and the US military. The US military was hoping to force the Sioux of this land, as gold had been discovered in this territory. The Sioux, however, had been living their for years and did not want to leave. This is why the conflict began. It was one of the most significant military victories for any Native American tribe against the US government. However, this would lead to increased troops/ action against the Sioux to force them off the land.