The correct answer is C) November of 1860: Abraham Lincoln is elected president.
The election of Abraham Lincoln is eventually going to lead to all of the other events mentioned in the answer choices. A few short weeks after Lincoln becomes president, South Carolina leaves the Union. After that, four more states will follow suit. Eventually, there will be a military conflict between the United States and the newly formed Confederate States of America at Fort Sumter in South Carolina. This results in the beginning of the American Civil War.