Identify the factors that were responsible for the shrinking size of the american middle class after the early 1970s.
a) the emergence of the low-wage service sector
b) greater demand for higher-skill jobs
c) a more regressive federal income tax
d) an expanding income gap between the highest paid executives and employees in the middle ranks

Explanation:

There were many factors that contributed to the shrinking of the american middle class in the 1970s, first of all the the emergence of the low-wage service sector  (mainly blue collar job positions) and on the other hand a  greater demand for higher-skill jobs for top companies which led to an expanding income gap between the highest paid executives and employees in the middle ranks

b]to spread the message of black power