In the past 30 years,the ability of unions to increase wages and improve working conditions for their members has:

A) increased.
B) decreased.
C) remained constant.
D) proved the marginal productivity theory of income distribution to be false.

Working Conditions

The environment, terms, and circumstances under which employees work, including aspects like hours, safety, rights, and wages.

Marginal Productivity

The additional output produced as a result of employing one more unit of a factor of production, holding all other factors constant.