A firm wants to minimize the total cost of producing 100 tons of dynamite. The firm uses two factors of production, chemicals and labor. The combination of chemicals and labor that minimizes production costs will be found where: Select one: a. the production of an additional unit of dynamite costs the same regardless of whether chemicals or labor are used. b. the ratio of the amount of chemicals used to the amount of labor used equals the ratio of the marginal product of chemicals to the marginal product of labor. c. None of these d. the ratio of the amount of chemicals used to the amount of labor used equals the ratio of the price of chemicals to the wage rate. e. the marginal products of chemicals and labor are equal