Final answer:
The Thirteenth, Fourteenth, and Fifteenth Amendments were designed to guarantee and protect the citizenship and civil rights of African Americans, with a focus on abolishing slavery, ensuring citizenship and equal protection, and safeguarding the voting rights of Black men.
Step-by-step explanation:
The main purpose of the Thirteenth, Fourteenth, and Fifteenth Amendments, ratified shortly after the end of the Civil War, was B) To guarantee and protect the citizenship and civil rights of African Americans. The Thirteenth Amendment abolished slavery in the United States, ensuring that no form of involuntary servitude would exist within the country except as punishment for a crime. Following this, the Fourteenth Amendment was pivotal in granting African Americans citizenship and ensuring equal protection under the law for all people, as well as prohibiting states from depriving any person of life, liberty, or property without due process. The Fifteenth Amendment focused specifically on suffrage, protecting the rights of Black men to vote, regardless of their race, color, or previous condition of servitude, marking a significant step towards racial equality in the democratic process.