Shipp Corporation had the following operating results in February 2023. Sales (8,000 units) $480,000 Variable expenses 336,000 Contribution margin 144,000 Fixed expenses 141,200 Net operating income $2,800 Required: a. What is the contribution margin per unit? b. If sales decline to 7,800 units, what would be the estimated net operating income? c. If the variable cost per unit increases by $4, spending on advertising increases by $1,000, and unit sales increase by 3,000 units, what would be the estimated net operating income? d. What is the break-even point in dollar sales? e. Estimate how many units must be sold to achieve a target profit of $50,000. f. What is the margin of safety percentage? g. Using the degree of operating leverage, what is the estimated percent increase in net operating income of a 10% increase in sales volume?