The correct answer is B. To preserve competition among business firms
Explanation:
The Federal Antitrust laws are a set of laws that regulate business actions in the national level in the United States, these laws include forbidding business from fixing prices, being involved in collusion or any other action that leads to abuse of power or monopolies. Due to this, the main purpose of these laws is to guarantee business have opportunities to compete that implies there are no monopolies and the customer has a wide range of options in terms of products and the business companies that produce them. Thus, the purpose of these laws is "to preserve competition among business firms".
Lincoln had to deal with not only the challenge of the South seceeding from the United States, but also the challenge of raising an army from Northern States who didn't want to get into a war.