Creekside Corporation data is as follows: Selling price is $75 per unit; Variable expenses are $45 per unit (60% of sales), and contribution margin is $30 per unit (40% of sales). Fixed expenses are $75,000 per month and the company is selling 3,000 units per month. a. The marketing manager believes that an $8,000 increase in the monthly advertising budget would increase monthly sales by $15,000. Should the advertising budget be increased?