Final answer:
The event most responsible for triggering the Civil War was Abraham Lincoln's 1860 election, which was a turning point after a series of divisive events, such as the Compromise of 1850 and the Kansas-Nebraska Act. The correct option is C.
Step-by-step explanation:
The event most responsible for triggering the Civil War was Abraham Lincoln's 1860 election.
This event was the culmination of increasing tensions between the proslavery South and the antislavery North, which saw several southern states secede from the Union to form the Confederate States of America (CSA), thus setting the stage for the Civil War.
While events such as the Compromise of 1850 and the Kansas-Nebraska Act significantly contributed to the mounting sectional tensions, it was Lincoln’s election that acted as the final catalyst, with his stance against the expansion of slavery being intolerable to the southern states.
Previous attempts to deal with the slave/free territory issue, such as in the Compromise of 1850 and the Kansas-Nebraska Act, did contribute to the overall climate of division. Historian James McPherson, for instance, considered the Kansas-Nebraska Act as potentially the single most critical event driving the nation towards conflict.
However, it was Lincoln's presidency that foreshadowed the start of the Civil War as it represented a fundamental and inalterable shift in the nation's leadership on the issue of slavery, which the southern states would not abide. The correct option is C.