The Number of Unskilled Workers Employed Before and After a Change

The number of unskilled workers employed before and after a change in the minimum wage is found to be the same.This means

A) the minimum wage change did not affect the labor market.
B) nothing, unless we know that the number of hours worked by each worker has not changed.
C) the minimum wage could be below the equilibrium value for unskilled labor.
D) either b or c
E) none of the above