The correct answer is true.
It is true that during the Civil War, the North effectively used the strategy of total war to weaken the South.
Total war means the usage of any kind of weapons, the territory, the combat and the soldiers. The Union used total war strategy to win the war at all cost. The Union considered military targets civilian and basic infrastructure in the South. That is why it was lethal. The total war strategy of the Union caused the Southern economy to suffer.