Schrute Farm Sales buys portable generators for $480 and sells them for $720. He pays a sales commission of 5% of sales revenue to his sales staff. Mr. Schrute pays $7,000 a month rent for his store, and also pays $2,200 a month to his staff in addition to the commissions. Mr. Schrute sold 600 generators in June. If Mr. Schrute prepares a contribution margin income statement for the month of June, what would be his contribution margin? A. $432,000 B. $309,600 C. $122,400 D. $741,600