Final answer:
The 15th Amendment required additional enforcement because Southern states implemented Jim Crow laws to prevent African Americans from voting, despite the protections meant to be provided by the 14th Amendment and the Reconstruction Acts.
Step-by-step explanation:
The amendment in question is the 15th Amendment, which required additional enforcement because southern states created loopholes to prevent African Americans from voting (Option B). After the end of the Civil War, the 14th Amendment made African Americans citizens and was intended to protect citizens from discriminatory state laws. However, many Southern states implemented policies and practices such as literacy tests, poll taxes, and white-only primaries, collectively known as Jim Crow laws, to circumvent these constitutional protections and maintain white supremacy. To combat these discriminatory practices, legislation such as the Voting Rights Act of 1965 and court rulings like Harper v. Virginia Board of Elections were necessary to enforce voting rights protections.