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 labor16,250

Variable factory overhead29,250

Fixed factory overhead26,000136,500

Operating expenses:

Variable operating expenses$6,010

Fixed operating expenses3,2209,230

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

a.$519,870

b.$510,770

c.$425,590

d.$422,370