Which amendment ended Prohibition in the United States?

The 21st Amendment is the correct answer because it specifically repealed the 18th Amendment, which had established Prohibition in the United States. Prohibition, enacted in 1920, made the manufacture, sale, and transportation of alcoholic beverages illegal. The 21st Amendment, ratified in 1933, marked the end of this period by allowing alcohol to be legally manufactured, sold, and consumed once again.

In contrast, the 19th Amendment granted women the right to vote, the 18th Amendment initiated Prohibition itself, and the 15th Amendment prohibits the denial of the right to vote based on race, color, or previous condition of servitude. These amendments address different aspects of American law and civil rights but do not pertain to the status of alcohol regulation in the United States.