Supporters of the sherman antitrust act of 1890 believed that regulation of

Regulation of competition between businesses", is the right answer.

Explanation:

The Sherman Antitrust Act of 1890 is was an antitrust law in the U.S. This Act places contention among various firms and companies, which was authorized by Congress following the presidency of Benjamin Harrison. This law limits (1) anti-competitive negotiations and (2) single system that monopolizes or seeks to monopolize the relevant industry. Its repudiation of the cartel was also estimated to make proscribed many labor union activities.

whats the question? im not quite understanding your question.