Cromwell Furniture Company manufactures sofas for distribution to several major retail chains, The following costs are incurred in the production and sale of sofas: n. Salesperson's salary, $80,000 plus 4% of the selling price of each sofa sold o. Foam rubber for cushion fillings p. Janitorial supplies, $2,500 per month q. Employer's FICA taxes on controller's salary of $180,000 r. Salary of designers s. Wages of sewing machine operators t. Sewing supplies