A car rental company is developing a replacement plan for its car fleet over the next 4 years. Based on past data, they have estimated all costs associated with replacement of individual cars within this planning horizon. All costs such as purchasing, operating, maintenance, and resale, associated with the policy to buy a car in year i and sell it in year j, is denoted as c, and is estimated for the whole planning horizon (in x$1000. All replacements (buying and selling) are assumed to occur at the beginning of the indicated years, and a car must be in service for at least one year before replacement is considered. What is the least cost replacement policy?

and a car must be in serv e replacement is considere cement policy