Final answer:
The word that best completes the list is 'd. Antitrust', as it refers to the Sherman Anti-Trust Act's purpose of preventing monopolies and promoting market competition.
Step-by-step explanation:
The word that best completes the list is d. Antitrust. In the context of industrialization and the growth of big businesses, the Sherman Anti-Trust Act was a federal law enacted in 1890 to combat the issue of monopolies and encourage competition in the marketplace. This act targeted large firms and trusts that used their market power to restrict trade and limit competition. The aim of these regulations was to prevent business practices that would lead to an unfair market monopoly, expand markets by breaking up monopolies, and facilitate capital accumulation by ensuring that firms could not artificially inflate prices and stifle competition.