[4 pts.] Capital recovery (CR) and the annual worth of the annual operating costs (AOC) of a currently installed machine, over years 1 to 5, is given in the following table (the machine has a useful life of 5 years). Year: 1 4 5 23 -46,000 -41,000 -34,000 -27,000 CR (S/year) -50,000 AW of AOC (5/year) -23,000 -25,000 -29,000 -35,000 -45,000 The economic service life (ESL) of the machine is Select one: a. 3 years b. 2 years 0 c. 4 years 0 d. 1 year e. 5 years