Corey must choose between two different designs for a safety enclosure, which will be in use indefinitely. A salvage value can be estimated for model A using a depreciation rate of 40 percent and declining-balance depreciation, while a salvage value for model B can be estimated using straight-line depreciation and the knowledge that after one year its salvage value will be $7500. Interest is 14 per cent. Use AW analysis to choose the best design