The answer would be C., Suversive activity.
Subversive activity refers to all willful acts that have the intention of being detrimental to governmental interests that don't really fall into the specific categories of; treason, sedition, sabotage... etc
Its C I believe.
Hope it helps
The Battle of the Little Bighorn, fought on June 25, 1876, near the Little Bighorn River in Montana Territory, pitted federal troops led by Lieutenant Colonel George Armstrong Custer (1839-76) against a band of Lakota Sioux and Cheyenne warriors. Tensions between the two groups had been rising since the discovery of gold on Native American lands. When a number of tribes missed a federal deadline to move to reservations, the U.S. Army, including Custer and his 7th Calvary, was dispatched to confront them.
The answer is 2 the efficiency of American textile production increased