The beginning inventory consists of 6,000 units, all of which are sold during the period. The beginning inventory fixed costs are $20 per unit, and the variable costs per unit are $90 per unit. Assuming no ending inventory, what is the difference in operating income between variable and absorption costing?

a. Variable costing operating income is $540,000 less than under absorption costing.

b. Variable costing operating income is $600,000 greater than under absorption costing.

c. Variable costing operating income is $120,000 less than under absorption costing.

d. Variable costing operating income is $120,000 greater than under absorption costing.