Hello!
The correct answer to this question is C.
The 13th Amendment simply banned slavery, but it did not give former slaves full rights. This amendment was later followed by the 14th Amendment, which granted African Americans citizenship. In addition, the 15th Amendment was later passed, which allowed African Americans and former slaves to vote.
Although African Americans did not have full rights, these three amendments greatly benefitted them and lead to much progress regarding race and discrimination.
I hope this helps you!