Wilson Company produces headsets for computers, which it sells for $40 each. Each headset costs $12 of variable costs to make. During April, 900 headsets were sold. Fixed costs for April were $8 per unit for a total of \$7,200 for the month. How much does Wilson's operating income increase for each $1,000 increase in revenue per month? $700 $800 $1,000 $300 Not enough information to determine the