What was ironic about the election of Andrew Johnson?

A) He was the first slaveholder to become president.
B) A man from a state that had seceded was now president.
C) An illiterate man was president.
D) A Ku Klux Klan leader ascended to the presidency.
E) Abraham Lincoln now regretted choosing Andrew Johnson as his vice president.

Andrew Johnson, who was from Tennessee, a state that had seceded from the Union during the Civil War, became president after the assassination of Abraham Lincoln. This was ironic because he was a leader from a Confederate state who ascended to the presidency of a nation that had just fought to preserve the Union against the Confederacy.