Please explain and show work

The following information pertains to Stone Wall Corporation: Beginning fixed manufacturing overhead in inventory Ending fixed manufacturing overhead in inventory Beginning variable manufacturing overhead in inventory Ending variable manufacturing overhead in inventory $75,000 45,000 30,000 20,000 Fixed selling and administrative costs Units produced Units sold $77,000 5,300 units 4,600 units What is the difference between operating incomes under absorption costing and variable costing? O A. $15,000 O B. $40,000 O C. $10,000 OD. $30,000