If We Were to Observe Above-Equilibrium Wages in a Particular

If we were to observe above-equilibrium wages in a particular labor market, then a possible explanation might be that

A) the theory of efficiency wages holds true for that market.
B) there is a powerful labor union representing workers in that market.
C) workers are largely unskilled and/or inexperienced and minimum-wage laws are effectively holding wages up in that market.
D) All of the above are correct.