4 (12 pts) A city is planning to invest in potential projects with the estimated cash flows below. Given that interest rate is 4.880884817% per semiannual, determine which option is preferable if options are mutually exclusive using PW analysis. $-12600 $-2100 Alternative First Cost AOC, per Year Annual Increase in Operating Cost, per Year Salvage Value Life, Years D $-6900 $-1050 $-120 $90 5 $2400 Effective interest rate: il = i) alternative C has life time of infinity ii) Alternative C has 10 years life time