The main strategy that president Roosevelt's administration used to stop the type of business practices criticized in this excerpt was to

"I hold that a corporation does ill if it seeks profit in restricting production... or seeking to achieve monopoly by illegal... treatment of its competitors... If, on the other hand, a corporation seeks profit sole by... treating the public... and its rivals fairly: then such a corporation is behaving well. It is an instrumentality of civilization operating to promote abundance by cheapening the cost of living so as to improve conditions everywhere throughout the whole community." ~ Theodore Roosevelt: An Autobiography, 1913

use the Sherman Antitrust Act to ensure competition in industry

Explanation:

Sherman Antitrust Act was passed by the United States Congress in 1890. The purpose of the Act is to prevent any form of monopoly or organized form of arrangement among varying business firms to dictates the prices of commodities for the consumers.

In other words, the purpose of the Sherman Antitrust Act was to allow for fair competition and economic advantage to both other producers and the consumers as well.

Hence, in this case, the correct answer is "using the Sherman Antitrust Act to ensure competition in the industry."

norsemen from northern countries had made earlier journeys

the doctrine of nullification recommended that states living inside the union have the one-sided, inalienable ideal to void any law made by the national government that could be esteemed illegal.

the united states was shaped based on a general agreement among its individual states. hence, it is inferred that under the hypothesis of invalidation, since the states are the establishment of the union, they have the ability to referee and disprove unlawful laws.