Which amendment abolished slavery in the United States?

The Thirteenth Amendment is the correct choice because it explicitly abolished slavery and involuntary servitude in the United States, except as punishment for a crime. Ratified on December 6, 1865, this amendment marked a significant turning point in American history by legally ending the institution of slavery, which had profound social, political, and economic implications for the country and for millions of individuals who had been enslaved.

The other amendments mentioned do not pertain to the abolition of slavery. The Ninth Amendment deals with the enumeration of rights not specifically mentioned in the Constitution, the Fifteenth Amendment addresses voting rights regardless of race, and the Eighteenth Amendment established Prohibition, which banned the manufacture, sale, and transportation of alcoholic beverages. Each of these amendments serves different purposes in terms of civil rights and governance but does not relate to the issue of slavery.