Which of the Following Statements Measures the Effectiveness of the Plan

Which of the following statements measures the effectiveness of the plan to disenfranchise blacks?

A) Republicans won the 1896 presidential election.
B) Not until the mid-twentieth century did black women gain voting rights.
C) As late as 1940, a very low percentage (3 percent) of adult black southerners were registered to vote.
D) During the Progressive era, black people were barred from participating in political debates
E) By 1920, more blacks lived in cities than in rural areas.