Feather Friends, Inc., distributes a high-quality wooden birdhouse that sells for $80 per unit. Variable expenses are $40.00 per unit, and fixed expenses total $180,000 per year. Its operating results for last year were as follows: 180, ooo 900, ooe Sales Variable expenses Contribution margin Fixed expenses Net operating income $ 2,160, oe 1, oee 1,080, oeo