Which act specifically prohibited contracts or combinations that restrained trade?

The Sherman Antitrust Act of 1890 is correctly identified as the act that specifically prohibited contracts or combinations that restrained trade. This legislation was a landmark in U.S. antitrust law, aiming to combat monopolistic practices and promote fair competition. The act made it illegal to restrain trade or commerce among the several states or with foreign nations, targeting the growing concentration of corporate power and monopolies that emerged during the late 19th century.

The significance of the Sherman Act lies in its broad application against any form of anticompetitive conduct, including trusts and monopolies, thus laying the groundwork for future legislation in regulating corporate practices. This act established the federal government's role in regulating the economy and protecting consumers from unfair business practices.

In contrast, while other acts like the Clayton Antitrust Act (1914) built upon the Sherman Act by addressing specific practices that the earlier legislation did not define, the Volstead Act pertains specifically to the enforcement of Prohibition, and the Interstate Commerce Act focuses on regulating the railroad industry and preventing unfair practices in the transportation sector.