casper boat parts, inc. is considering two different production lines for use in its assembly plant: ⚫ first line costs $15,000 and requires $3,000 in annual operating expenses. it will have a $5,000 salvage value at the end of its three-year service life. ⚫ second line costs $20,000 but requires only $2,000 in annual operating expenses. it will have an $8,000 salvage value at the end of its four-year service life. the firm’s marr is 12%. assuming that a line is needed for 12 years and that no significant changes are expected in the future price and functional capacity of both lines, select the most economic line based on equivalent annual cost analysis (computing naw for each line).