What do three american megalopolises have in

The concept of megalopolis or  "great city" has been popularized by Jean Gottmann,  Megalopolis, with a capital "M," started from the urban region of southern New Hampshire to northern Virginia which sprung up to eight other regions around the world. What the three American Megalopolises have in common – a region needs to have an extensive network of metropolitan areas with a minimum population of  25 million with intense economic interaction.

answer:    

a.

explanation:

i do not know if this question has options, but a main impact of the federal reserve act of 1913, which created the federal reserve bank, was the international use of the u.s. dollar, which soon became the world's leading currency - particularly during world war i, since many nations around the world asked the united states for money.