The primary reason John Wilkes Booth assassinated President Abraham Lincoln was that he was angry about the Confederate defeat in the Civil War and believed that killing Lincoln would avenge the South and its cause. Therefore, the most accurate option is:
- Booth was angry about the Confederate defeat.
Booth, a staunch supporter of the Confederacy, viewed Lincoln's leadership as detrimental to the Southern cause and believed that the assassination would incite a resurgence for the Confederacy.