A constructionengineer has been asked to recomment an excavator for acquisition. Three alternatives have been identified, having the characteristics shown in the following table. $($MARR $=12\%)$

Excavator Alternative Useful life Investment Annual operation cost Terminal salvage value

A $4$ years $$15,500$ $$8,750$ $$2,500$

B $5$ years $$20,250$ $$5,850$ $$3,000$

C $6$ years $$30,750$ $$3,175$ $$3,250$

a$)$ Apply present worth analysis.

b$)$ Use shortest life to establish the planning horizon$$s length and apply present woth analysis again.

c$)$ Use longest life to establish the planning horizon$$s length and apply present woth analysis once more.

d$)$ Repeat PW analysis for $10$ years standard analysis period.

e$)$ Consider an infinitely long planning period and calculate the annual worth for each investment alternatives.