Data for Hermann Corporation are shown below: Selling price Variable expenses Contribution margin Percent Per Unit of Sales $ 80 44 100% 55 $ 36 45% Fixed expenses are $76,000 per month and the company is selling 2,500 units per month. Required: 1-a. How much will net operating income increase (decrease) per month if the monthly advertising budget Increases by $8,100, the monthly sales volume Increases by 100 units, and the total monthly sales increase by $8,000? 1-b. Should the advertising budget be increased?