A business received an offer from an exporter for 20,000 units of product at $15 per unit. The acceptance of the offer will not affect normal production or domestic sales prices. The following data are available: Domestic unit sales price $21 Unit manufacturing costs: Variable 12 Fixed 5 What is the amount of the gain or loss from the acceptance of the offer? a. $35,000 loss b. $40,000 gain c. $60,000 gain d. $50,000 gain