The best description of how the Fourteenth Amendment extended and limited civil rights to Black Americans is:
The Fourteenth Amendment defined citizenship in the U.S., made all citizens equal before the law, and guaranteed due process to all citizens; however, it did not extend voting rights to Black Americans or prevent the separate but equal doctrine.
This option accurately reflects the key elements of the Fourteenth Amendment, including its role in defining citizenship and ensuring equal protection and due process, while also acknowledging its limitations regarding voting rights and the subsequent establishment of the "separate but equal" doctrine.