A business operated at 100% of capacity during its first month, with the following results:

Sales (104 units)		$520,000
Production costs (130 units):
Direct materials	$65,000
Direct labor	16,250
Variable factory overhead	29,250
Fixed factory overhead	26,000	136,500
Operating expenses:
Variable operating expenses	$5,400
Fixed operating expenses	4,160	9,560

The amount of operating income that would be reported on the variable costing income statement is

a.$426,200

b.$510,440

c.$519,870

d.$396,040