What event caused four additional Southern states to secede from the Union?
A. The U.S. accepted West Virginia as a state.
B. The South fired on Fort Sumter.
C. Lincoln declared the Emancipation Proclamation.
D. Lincoln raised an army.
A. The U.S. accepted West Virginia as a state.
The correct answer is B. The South fired on Fort Sumter. This event, which occurred on April 12, 1861, marked the beginning of the American Civil War. Fort Sumter was a Union fort located in Charleston Harbor, South Carolina. When Confederate forces attacked and eventually captured the fort, it led to the secession of four additional Southern states: Virginia, Arkansas, Tennessee, and North Carolina.
To find the answer, you would need a basic understanding of the American Civil War and the events leading up to it. This information can be found in history books, online articles, or educational websites. By studying the sequence of events and the context of the situation, you can identify that the firing on Fort Sumter was the main trigger for these four states to secede from the Union.