If a Firm Is Hiring Variable Resources D and F $\mathrm { MP } _ { D } = \mathrm { MP } _ { F }$

Multiple Choice

If a firm is hiring variable resources D and F in perfectly competitive input markets, it will minimize the cost of producing any level of output by employing D and F in such amounts that

A) the price of each input equals its MP.
B) $\mathrm { MP } _ { D } = \mathrm { MP } _ { F }$
C) $\mathrm{MP} _ { D } / P _ { D } =\mathrm{MP} _ { F } / P _ { F }$
D) $\mathrm { MP } _ { D } / P _ { F } = \mathrm { MP }_ { F } / P _ { D }$