7. From the data shown, the economic service life of the asset is (Note: AW values represent values if asset is retained for number of years shown in left hand column) (a) 1 year (b) 2 years (c) 3 years (d) 4 years (e) 5 years Y ears Retained AW of First Cost, S AW of AW of Operating Cost, S Salvage Value, S 99,000 38,095 18,127 6,464 32% -165,000 -86,429 -60,317 -47,321 -39,570 -36,000 -36,000 -42,000 -43,000 -48,000 4