When the Civil War began, many tribal leaders believed the Union had failed to honor their treaties with the Five Tribes. Which of the following best describes what occurred?
A. The Union refused to continue to pay the annuities required by treaties.
B. The Union left the region and could no longer protect the tribes from attack.
C. The Union attacked forts controlled by the Five Tribes.
D. The Union drafted tribe members into Union regiments, sending them to fight against the Confederacy.