Which statement describes the long term impact of civil war

Complete question:

Which statement describes a long-term effect of the Civil War?

A) Military leaders began to run for political office more frequently.

B) The American population became more divided by regional cultural differences.

C) The president became a more important and powerful political figure.

D) African Americans began to exercise a significant amount of political power

C) The president became a more important and powerful political figure.

Explanation:

Prior to the civil war, the power of the states government can be considered to  be stronger than the Federal government. The constitution did not necessarily stated that the states had to completely obey the federal government.  So,  president was considered as somewhat a weak figure compared to State governor.

But, the civil war provided that a president can united several states in order to fulfill one single goal.

After the civil war, presidents started to be seen as a powerful political figure and officially strengthen the states' perception regarding the authority of the federal government.