A remotely located air sampling station can be powered by solar cells or by running an electric line to the site and using conventional power. Solar cells will cost $14,600 to install and will have a useful life of 4 years with no salvage value. Annual costs for inspection, cleaning, etc., are expected to be $1700. A new power line will cost $12,000 to install, with power costs expected to be $700 per year. Since the air sampling project will end in 4 years, the salvage value of the line is considered to be zero. At an interest rate of 6% per year, which alternative should be selected on the basis of a present worth analysis? Show your equations and solve problem using factors: solve it in Excel,