The Sherman Antitrust Act of 1890 signified that the era of trusts was ending. was strongly opposed by congressional Republicans. was strengthened by the courts over the next decade. was indifferently enforced and weakened by the courts. mirrored legislation passed earlier in New Jersey and Delaware.

The correct answer is the following: "was used by the federal government against labor unions and was indifferently enforced and weakened by the Courts".

Explanation:

The Sherman Antitrust Act, published on July 2, 1890, was the first measure of the US federal government to limit monopolies. The act declared the trust illegal, considering them restrictive for international trade. It was created by US Ohio Senator John Sherman, and approved by President Benjamin Harrison.

This law prohibits certain business activities that the federal government declares as acts of anti-competition and requires investigation to pursue large companies with power in the market.

It aims to prevent the artificial increase in prices by restricting the exchange or the material. The innocent monopoly is perfectly legal but acts by a monopolist to artificially preserve that status or vile contracts to create a monopoly, they are not. The purpose of the Sherman Act is not to protect competitors from damage by legitimacy.