题目内容：
The assetsection of the January 1, 20X9, balance sheet of Big Valley Company includes amachine which was acquired on January 1, 20X5. The machine.s original cost was $500,000, and the estimated life wasdetermined to be 10 years. The estimatedresidual value was zero, and the straight-line method of depreciation waschosen. The book value of the machine asof January 1, 20X9, is:A、$500,000
B、$450,000
C、$250,000
D、$300,000
参考答案：