Which of the following is not correct?

A) Other things equal,a monopsonist will pay a lower wage rate than will a firm hiring labor competitively.
B) A monopsonistic employer will pay workers a wage rate equal to their MRP.
C) A purely competitive seller will pay workers a wage rate equal to their MRP.
D) An imperfectly competitive seller will employ additional workers as long as the MRP of additional workers exceeds their MRC.

A monopsonistic employer will pay workers a wage rate lower than their MRP, as they have bargaining power due to their market dominance in hiring labor. A purely competitive seller will indeed pay workers a wage rate equal to their MRP, but not a monopsonistic employer. Option C is correct as it describes the behavior of a purely competitive seller. Option D is also correct as it follows the rational decision-making process of any firm, where they will hire additional workers as long as the MRP of additional workers exceeds their MRC. Therefore, option B is not correct as it contradicts the behavior of a monopsonistic employer.