The correct option is: "The United States."
In the nineteenth century, Prussia promoted a political plan that had the purpose of German unification. This, in addition, was closely linked to the economic development process of that country. However, this Bismarck project of the "Greater Germany" was not carried out until 1871, since the independent and Confederate States would not join. Nevertheless, these states evolved towards industrialization in an advantageous way, referring to the economic level, to this policy of unification several years before. This process resulted in the great industrialization of the country during the twentieth century, being one of the industrial powers of the time.