In monopsony:

A) each firm employs a small portion of the total supply of labor.
B) the workforce is highly mobile.
C) the wage rate paid by the employer varies directly with the number of workers employed.
D) the employer is a "wage taker."

In a monopsony, there is only one buyer (employer) in the market for labor, which gives the employer significant control over the wage rate. As the monopsonist hires more workers, the wage rate must increase to attract additional labor, since they face an upward-sloping supply curve for labor. This means the wage rate varies directly with the number of workers employed, unlike in perfectly competitive markets where employers are "wage takers" and do not have the power to set wages.