Answer:
d. the secession of the first group of southern states happened last.
Step-by-step explanation:
In 1861, several southern states, including South Carolina, seceded from the United States and formed the Confederate States of America. This was in response to the election of Abraham Lincoln as president, as well as other political and economic issues.
After the formation of the Confederate States of America, the first military action of the American Civil War was the firing on Fort Sumter in South Carolina on April 12, 1861.