A

During the Civil War, the Border States that included Kentucky, Delaware, Missouri, Maryland, and West Virginia were the slave states that didn’t leave the Union. They played a rather important role in the Union’s victory as they gave the advantage in money, factories, and troops.

Explanation:

The American Civil War was happening from 1861 to 1865 between the southern states that had formed the Confederacy after leaving the Union and the northern states that kept loyalty to the Union. There were five Border States, Kentucky, Delaware, Missouri, Maryland, and West Virginia that joined them a little later, but they were chosen not only geographically.

They also had a special cultural identity for three reasons. Firstly, slavery was legal in them; secondly, in the 1860 election, they didn’t support Lincoln. Finally, these states were holding on to a strong belief in a federal union and did not want to leave it.

The Border States’ significance was that they served a very important purpose and were rather vital to the Union’s success in the war. The value of them was that these states were huge agricultural areas that produced both grain and livestock and contained crucial deposits of mineral resources.

Moreover, the Border States had good communication and transportation systems and lines and gave the Union the advantage in money, troops, and factories, which was crucial to the war. Also, the state of Maryland was the only thing that was standing between Washington, D.C, the capital of the Union, and Virginia.

Additionally, the Border States were the main reason why president Lincoln was waiting so long before freeing people and abolishing slavery. As those five states were not against it and were vital for winning the war, President Lincoln decided to wait, please the Border States, win the war with their help, and then free the slaves.