c) South Carolina

South Carolina initiated the secession of Southern states from the Union, leading to the American Civil War. In December 1860, following the election of Abraham Lincoln, South Carolina became the first state to secede, citing the threat to slavery as its primary concern. This act set off a chain reaction, with other Southern states soon following suit, leading to the formation of the Confederate States of America. South Carolina’s secession played a pivotal role in the escalation of tensions that erupted into the Civil War.