Net Income Planning Superior Corporation sells a single product for $60 per unit, of which $36 is contribution margin. Fixed costs total $86,400 and net income before income tax is $28,800. Determine the following a. The present sales volume in dollars. $ b. The break-even point in units. units C. The sales volume in units necessary to attain a net income before income tax of $39,600 units d. The sales volume in units necessary to attain a net income before income tax equal to 20% of sales revenue. units e. The sales volume in units necessary to attain an after-tax net income of $43,200 if the tax rate is 40% units