A machine costs 50000 and it is estimated that it will be used for for 5 years. The estimated salvage value is 10,000 for this purchase. If the straight line depreciation is used, what will the remaining book value balance at the end of year 42 (Note: Find Bn remaining balance after calculating the annual deprecation allowance) Select one: O a. 8000 O b. 18000 O c. 10000 O d. 11000 O e. 16000 O f. 18000