Data concerning Amburn Corporation's single product appear below. Fixed expenses are $179,000 per month. The company is currently selling 3,000 units per month. The marketing manager would like to cut the selling price by $9 and increase the advertising budget by $12,000 per month. The marketing manager predicts that these two changes would increase monthly sales by 500 units. What should be the overall effect on the company's monthly net operating income of this change? Per Unit Percent of Sales Selling price..... $120 100% Variable expenses Contribution margin. 48 40% $ 72 60% Select one: a. decrease of $19,500 b. increase of $43,500 c. increase of $19,500 d. decrease of $7,500