Suppose Your Firm Is a Monopsonist Hiring Only One Variable

Suppose your firm is a monopsonist hiring only one variable input.If you want to maximize profits,you will purchase that variable input up to the point where the

A) cost of the input equals the profit generated by the employment of that input.
B) demand curve intersects the supply curve of the input.
C) marginal product of that input equals the price of one unit of the input.
D) wage rate is the highest.
E) MRP curve for the input intersects the marginal cost curve for the input.