Answer:
The correct answer is D: increase $6000
Step-by-step explanation:
Giving the following information:
Data concerning that product appear below: 
Selling price $ 170 100 % 
Variable expenses $68 40 % 
Contribution margin $ 102 60 %
 Fixed expenses are $521,000 per month. 
The company is currently selling 7,000 units per month. 
Management is considering using a new component that would increase the unit variable cost by $6. The marketing manager predicts that monthly sales would increase by 500 units
Now:
Sales= 7500 units
Variable cost= $74 per unit
Contribution margin= $97
Original income= 7000*102 - 521000= 193000
New income= 7500*96 - 521000= 199,000
Variation= +6000