It is true that unionized women earn, on average, more than a third more than nonunionized women do. But the unionized women work in industries where wages happen to be high, their nonunionized counterparts in these industries earn about as much as they do. Therefore unionization does not raise womenâ€™s wages.
Which of the following, if true, most seriously weakens the argument above?
(A) Besides wage increases, unions bargain for benefits such as medical insurance and workplace safety.
(B) The most highly paid women are in executive positions, which are not unionized.
(C) Wages in many industries vary from one part of the country to another, regardless of whether workers are unionized or not.
(D) Nonunionized women in an industry often receive income increases as a result of increases won by unions representing women who work for other employers in the same industry.
(E) The unionization of women who work for one employer in a given industry frequently prompts the unionization of women who work for other employers in the same industry.