$0$ union workers eam higher or lower wages than nonunion workers? Explain briefly.

A$.$ Union members earn more than nonunion members because unionization is higher in the United States than in most industrial countries.

B$.$ Union members earn less than nonunion members because unions decrease employment.

C$.$ Union members earn about the same amount as nonunion members at least partially because the share of national income received by workers has remained roughly constant.

D$.$ Union members earn more than nonunion members largely because unions bargain with employers for higher wages, at least partially with the threat of calling a strike.

E$.$ Union members earn more than nonunion members at least partially because union members work in industries where wages are relatively high regardless of unions.