Riverbed Cupcakes Co. is selling cupcakes for $6 for a box of one dozen. Riverbed has fixed costs equaling $49920 per year, and its accountant has calculated the monthly break- even at 1040 boxes sold. Which of the following statements is correct based on this information? O Variable costs equal $2 per box, and contribution margin is $4 per box. O Variable costs equal $3 per box, and contribution margin is $3 per box. Variable costs equal $4 per box, and contribution margin is $2 per box. O Variable costs equal $3.50 per box, and contribution margin is $2.50 per box