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% x units