During the Civil War, Texas troops serving in the Trans-Mississippi department helped to defend which area?

In 1863, General Edmund Kirby Smith took command of the Confederate Trans-Mississippi Department, and unsuccessfully tried to relieve the siege of Vicksburg by Lt. Gen. Ulysses S. Grant on the opposite eastern banks of the Mississippi River in the state of Mississippi.

the answers is b.   environments.

the correct answer is to reduce tax