The correct answer is D) using unfair business practices.
Trust-busting laws were focused on big companies that were using unfair business practices.
The United States federal government, led by President Theodore Roosevelt considered the formation of monopolies as an injustice to other American companies and competitors. That is why he decided to create legislation to end and control big companies. However, the next US President, William H. Taft, proved t be more committed to eliminating trusts and monopolies. Taft asked the Courts to participate in this regulation.