What legislation enacted in 1919 gave the power to enforce prohibition?

The Volstead Act is the correct answer because it provided the legal framework for the enforcement of Prohibition in the United States. Enacted alongside the 18th Amendment to the Constitution, which prohibited the manufacture, sale, and transport of intoxicating liquors, the Volstead Act defined the specific terms and conditions under which alcoholic beverages were regulated, effectively outlining what constituted "intoxicating liquors."

This legislation established the responsibilities of federal agents tasked with enforcing Prohibition laws and included provisions that defined exceptions, such as allowing certain types of non-intoxicating beverages and medicinal use of alcohol. The act was crucial in translating the broader mandate of the 18th Amendment into actionable law, leading to the enforcement measures that characterized the Prohibition era.

In contrast, while the other options reference legislation related to alcohol, they either did not exist or were not specifically responsible for enforcing Prohibition. For example, the Prohibition Act does not exist under that name, the Liquor Control Act generally relates to regulations established after Prohibition to manage alcohol distribution and sales, and the Temperance Act is not a specific legislative instrument enacted for the enforcement of the 18th Amendment.