Answer:
A. Tennessee had already been admitted into the Union upon ratifying the Fourteenth Amendment.
Explanation:
Tennessee had been the last state to withdraw from the Union and join the Confederacy, in June, 1861. Â It became the first state from the South to return to the Union on July 24, 1866. Â This was a week after Tennessee had ratified the 14th Amendment, which guaranteed the rights of citizenship to former slaves.