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

Sales (120 units)		$600,000
Production costs (150 units):
Direct materials	$75,000
Direct labor	18,750
Variable factory overhead	33,750
Fixed factory overhead	30,000	157,500
Operating expenses:
Variable operating expenses	$5,100
Fixed operating expenses	3,470	8,570

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

a. $459,430

b. $591,430

c. $599,850

d. $492,900