Loren Company's single product has a selling price of $15 per unit. Last year the company reported total variable expenses of $180,000, fixed expenses of $90,000, and a net operating income of $30,000. A study by the sales manager discloses that a 15% increase in the selling price would reduce unit sales by 10%. If her proposal is adopted, net operating income would:

a. increase by $45,000

b. increase by $28,500

c. increase by $37,500

d. increase by $7,500