Cost behavior Flaherty Accounting Services pays $400 per month for a tax preparation software license. In addition, variable charges incurred average $9 for every tax return the firm prepares. a. Determine the total cost and the cost per unit if the firm expects to prepare the following number of tax returns in March: Note: Round amounts to two decimal places. No. of Tax Returns Total Cost Cost per Tax Return 1. 40 $ 2. 3. 100 160 $ $ $ $ b. The owner of Flaherty Accounting Services wants to earn a margin (excluding any other direct costs) on tax returns of $3,000 during March. If 40 returns are prepared, what tax return preparation fee should be charged? c. If the fee is charged in part b and 160 returns are prepared, what is the margin in March?