Final answer:
The question is about the event that led to the secession of many Southern states from the Union.
Step-by-step explanation:
The subject of this question is History. The question is asking about the event that led to the secession of many Southern states from the Union. The correct answer is OC. Abraham Lincoln's election. Following Lincoln's election in 1860, several Southern states seceded in response to his anti-slavery stance, which they perceived as a threat to their economy and way of life.
Learn more about Causes of Southern states' secession from the Union