Identify and describe the 6 different kinds of U.S citizens characterized in the study by Verba and Nie.
a) Activists, voting specialists, communalists, parochial participants, voting mobilizers, and non-voters
b) Democrats, Republicans, Independents, Socialists, Libertarians, and Green Party members
c) Blue-collar workers, white-collar workers, farmers, entrepreneurs, academics, and artists
d) Baby boomers, Generation X, Millennials, Generation Z, Silent Generation, and Greatest Generation