Which of the following was a problem that led to the Civil War?

The issue of slavery and sectionalism was a fundamental problem that ultimately led to the Civil War. During the 19th century, the United States was deeply divided over the issue of slavery, particularly between the Northern states, which were generally opposed to its expansion, and the Southern states, which relied heavily on slavery for their agrarian economies. This division created sectional tensions that influenced political decisions, social dynamics, and economic interests.

As the country expanded westward, the question arose whether new territories and states would allow slavery, further intensifying the conflict between the North and South. The Missouri Compromise, the Compromise of 1850, and the Kansas-Nebraska Act are examples of legislative efforts to address these tensions, but they ultimately failed to resolve the underlying issues. Additionally, the rise of abolitionist movements in the North and the entrenched pro-slavery sentiments in the South heightened animosities.

Consequently, slavery was not only an economic issue but also a significant moral and social one, leading to polarization and strife that contributed to the outbreak of the Civil War in 1861. This makes the issue of slavery and sectionalism the correct answer, as it was the primary catalyst for the conflict between different regions of the country.