The Development of a "Mass Culture" in the 1920s Refers

The development of a "mass culture" in the 1920s refers to

A) the death of the Democratic party and the idea that everyone shared the same political party.
B) the rise of national brands, advertising, and radio and film releases with a national audience.
C) the relative lack of immigration during the period, which caused there to be few ethnic groups.
D) the growth of shared opinions on science and technology in the face of impending war.
E) modernism's popularity across the United States, uniting Americans in a shared artistic culture.