A firm will hire a unit of input only if its

A) marginal physical product and marginal revenue product are positive.
B) marginal physical product and marginal revenue product are negative.
C) marginal physical product is positive and whose marginal revenue product is negative.
D) marginal physical product is negative and whose marginal revenue product is positive.

Marginal Physical Product

The change in total physical output that results from a one-unit increase in the quantity of one input, holding other inputs constant.

Marginal Revenue Product

The extra income derived from the use of an additional unit of a resource or input in production.

Input

Resources such as labor, materials, and capital that are used in the production process to create goods and services.