Final answer:
The end of the American Civil War is marked by the surrender of Confederate General Lee to Union General Grant at the Battle of Appomattox Court House on April 9, 1865.
Step-by-step explanation:
The event recognized as the end of the American Civil War is D. The Battle of Appomattox Court House. On April 9, 1865, Confederate General Robert E. Lee surrendered his army to Union General Ulysses S. Grant at Appomattox Court House in Virginia. This act effectively brought an end to the Civil War, as it signified the defeat of the Confederacy. The other options listed, such as the election of Abraham Lincoln or the secession of South Carolina, were significant events that contributed to the start and escalation of the war but were not its conclusion.