Which of the following statements best summarizes a distinction mentioned in the passage between public-sector employment and those of private-sector employment'

A． Private-sector work involves a lesser degree of immigrant competition than public-sector work.
B． A growing educational level has assisted African Americans find work in the private-sector more than it has done so in the public-sector.
C． Immigrant population gains have benefited workers in the public-sector more than they have workers in the private-sector.
D． Private-sector work often requires less in the way of educational credentials than public-sector work.
E． The private-sector tends to contain stronger ethnic networks than the public sector.