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