Which of the following statements is FALSE? a.
The Confederate Constitution made it illegal to free a slave in the South.
b.
Texas joined the Confederate States of America and seceded from the Union.
c.
Elected officials in Texas were required to take an oath of loyalty to the Confederacy after Texas seceded.
d.
After Lincoln was elected President, new territories that originally wanted to join the Union joined the Confederacy instead.

I know the answer and since I can't answer my own question I'm writing it up here.

The answer is - D