Which of the Following Sets of Circumstances Is Likely to Provide

Which of the following sets of circumstances is likely to provide the best evidence in support of the theory of efficiency wages?

A) Workers in the market are unskilled and not represented by a union, and their wage exceeds the equilibrium wage.
B) Workers in the market are highly skilled and not represented by a union, and their wage exceeds the equilibrium wage.
C) Workers in the market are highly skilled and represented by a union, and their wage exceeds the equilibrium wage.
D) Employers in the market are known for reducing the workers' wage whenever they get an opportunity to do so.