Kayler Construction Co. must choose between two sources of heavy-duty drilling equipment. Drill A costs $7,500 and will be depreciated straight line over its five year life. The (pre-tax) maintenance costs for Drill A are $150 per year. In contrast, Drill B costs $9,000 and will be depreciated straight line over its sevenyear life. The (pre-tax) maintenance costs for Drill B are $120 per year. You should assume that Kayler must have this type of drilling equipment to stay in business, so whichever drill they buy, they will replace it when it wears out. Each drill will have zero salvage value at the end of its useful life. The required rate of return for Kayler Construction is 8.5 percent and the tax rate is 21%. Which drill should Kayler purchase and why?