Question 13 4 pts A machine was purchased for $42,000 on the first day of the first year. It has an estimated useful life of four years and a $6,000 estimated salvage value. Using straight-line depreciation, what is the asset's carrying value (net book value) at the end of the THIRD year? O $ 6,000. O $ 15.000. $ 9,000 O S 10.500