Answer:
Option b: amount by which a firm's total resource cost increases as the result of hiring one more unit of the resource.
Explanation:
Marginal resource cost is the amount that additional unit of a resource brings or contributes to the firm's total resource cost individually.
Marginal Resource Cost is simply the change in total resource cost divided by a one-unit change in resource quantity. A firm will hire resources until MRP=MRC. The determinants of resource demand are the changes in the demand for the product produced, changes in the productivity of the resource, and changes in the prices of other resources.