How did the Northern blockade affect the Confederate's war effort and economy?

During the Civil War, the Union attempted to blockade the southern states. A blockade meant that they tried to prevent any goods, troops, and weapons from entering the southern states. By doing this, the Union thought they could cause the economy of the Confederate States to collapse.

Explanation:

i think it would be reparing roads  

the answer is a. since they were a huge producer of cotton and wanted the most money for it.