Final answer:
Congressional Reconstruction allowed African Americans to gain voting rights and access to education and employment, marking a period of significant change, although later undermined by Jim Crow laws.
Step-by-step explanation:
The best description of how Congressional Reconstruction changed life for African Americans in the South is that they gained voting rights and access to education and employment opportunities. Following the Civil War, Reconstruction marked a period where African Americans began to win elections across the South, and the 15th Amendment prohibited disenfranchisement based on race, which was supposed to guarantee African American men the right to vote. Despite these advances, it's important to note that this progress was met with resistance and was short-lived as Jim Crow laws and various methods of disenfranchisement emerged to undermine these gains. The establishment of public school systems was a significant achievement during this time, although segregation still persisted in many areas.