Final answer:
Sitting Bull, the Lakota Sioux spiritual leader, led a brilliant strike against the U.S. Army in 1866 in the Battle of Little Bighorn, resulting in the defeat of Colonel George Custer and his men.
option c is correct.
Step-by-step explanation:
The Lakota Sioux spiritual leader Sitting Bull led a brilliant strike against the U.S. Army in 1866 in the Battle of Little Bighorn. Sitting Bull united multiple tribes and successfully defended their lands against the U.S. Army's Seventh Cavalry led by Colonel George Custer.
This battle resulted in the defeat of Custer and his men, making it the single greatest loss of U.S. troops to a Native American force during the era of westward expansion.