Beckman Enterprises purchased a depreciable asset on October 1, Year 1 at a cost of $100,000. The asset is expected to have a salvage value of $20,000 at the end of its five-year useful life. If the asset is depreciated on the double-declining-balance method, the asset's book value on December 31, Year 2 will be: （ ）
选项：

A:$54,000
B:$90,000
C:$16,000
D:$36,000