An electronics manufacturer is considering the buy of one of two types of laser trimming devices. The sales forecast indicated that at least 8,000 units will be sold for each year. Device A will raise the annual fixed cost of plant by $20,000 and will reduce variable cost by $5.60 per unit. Device B will increase the annual fixed cost by $5,000 and will reduce variable cost by $3.60 per unit. If variable costs are now $20 per unit produced, which device should be purchased?