Final answer:
The primary source likely discusses the increasing sectional tensions between the North and the South around 1820, pointing to the issue of slavery as a central factor that would eventually lead to the Civil War.
Step-by-step explanation:
The primary source in question likely discusses the growing sectional tensions that characterized the United States around 1820. Option A is the correct answer; it highlights the growing tensions between the North and the South. This period saw critical debates over slavery and its expansion westward, which increasingly divided the nation.
The Missouri Compromise of 1820 was one such attempt to manage these divisions by maintaining a balance between free and slave states. However, as the United States acquired more land and different economic interests continued to evolve, these solutions were temporary. The Compromise of 1850 was another significant attempt to ease tensions by addressing the status of new territories and states regarding slavery. Such measures could not ultimately prevent disunion, leading to the Civil War in the 1860s.