Required information [The following information applies to the questions displayed below.] Data for Hermann Corporation are shown below: Selling price. Variable expenses Per Unit $ 125 Percent of Sales 100% 80 $45 64 36% Contribution margin Fixed expenses are $85,000 per month and the comparty is selling 2,700 units per month. Required: 1-a. How much will net operating income increase (decrease) per month if the monthly advertising budget increases by $9,000, the monthly sales volume increases by 100 units, and the total monthly sales increase by $12,500? 1-b. Should the advertising budget be increased?