Trust busting laws were focused on big companies that were

A. On the verge of going bankrupt

B. Treating competitors fairly

C. Weak and struggling to survive

D. Using unfair business practices

D. Using unfair business practices.

Explanation:

Trust busting laws were focused on discouraging big companies on the use of business practices that favored monopolisitic ways and treated competitors in an unfair way. The Standard Oil Company, property of John D. Rockefeller, was one example of such monopolistic practices.