Required information [The following information applies to the questions displayed below.] Data for Hermann Corporation are shown below: Fixed expenses are $70,000 per month and the company is selling 4,000 units per month. Required: -a. How much will net operating income increase (decrease) per month if the monthly advertising budget increases by $11,000, the nonthly sales volume increases by 100 units, and the total monthly sales increase by $5,000 ? b. Should the advertising budget be increased