Final answer:
The South's defeat in the Civil War can be attributed to a combination of Union strategies, such as the Vicksburg Campaign and Sherman's March to the Sea, as well as General Ulysses S. Grant's effective use of the Union's superior resources and manpower. so, option d is the correct answer.
Step-by-step explanation:
Reasons for the South's Defeat in the Civil War
Many factors contributed to the South's defeat in the Civil War. Among them, the choice of Robert E. Lee as an innept general is not widely supported as the main cause. Instead, significant events such as the Union's Vicksburg Campaign, which resulted in Union control of the Mississippi River, and Lee's defeat at Gettysburg, put the Confederacy at a disadvantage. The Union's total war strategy, exemplified by General Sherman's March to the Sea, devastated the South's infrastructure and morale, greatly contributing to the Confederate defeat. Moreover, General Ulysses S. Grant's relentless approach, utilizing the Union's superior numbers and resources, wore down the Confederate forces.
Although President Jefferson Davis's central government faced internal dissent and lacked a general-in-chief for much of the war, it was ultimately the combination of these factors, including military strategy and resources, that led to the South's defeat.