Mi Tierra Driving School charges $680 per student to prepare and administer written and driving tests. Variable costs of $408 per student include trainers' wages, study materials, and gasoline. Annual fixed costs of $63,920 include the training facility and fleet of cars. Read the requirements. Requirement 1. For each of the following independent situations, calculate the contribution margin per unit and the breakeven point in units: Begin by showing the formula for contribution margin per unit and then enter the amounts to calculate the contribution margin per unit for each situation. (Abbreviation used: CM = contribution margin.) CM per unit Situation a. Situation b. Situation c. Situation d. = Now select the labels to show the formula for breakeven point in units and then enter the amounts to calculate the breakeven point in units for each situation. (Complete all answer boxes. Abbreviation used: CM = contribution margin.) Required sales in units Situation a. Situation b. + = Situation c. + = Situation d. Requirement 2. Compare the impact of changes in the sales price, variable costs, and fixed costs on the contribution margin per unit and the breakeven point in units. First, compare the impact of changes in the sales price, variable costs, and fixed costs on the contribution margin per unit. The contribution margin when the fixed costs decrease. when the sales price decreases. The contribution margin Now, compare the impact of changes in the sales price, variable costs, and fixed costs on the breakeven point in units. when the sales price decreases. The breakeven point The breakeven point fixed costs decrease. when variable costs decrease. The contribution margin when the variable costs decrease. The breakeven point when