4. A networked computer system costs $80,000 with useful life of 6 years. Assume that the estimated salvage value is $5,000. Compute the annual depreciation allowances and the resulting book value, initially using the DDB and then switch to SL to obtain the maximum tax-deferring benefit of depreciation. Mark clearly in which year you switch to SL. (20 points) Bn ($) Year (0) Dn using SL(S) Dn using DDB (5) 80,000