Morten Co., which uses the double-declining-balance method of depreciation, purchased a new machine on January 1, 2018. The machine cost $160,000, had an estimated useful life of 8 years and $20,000 residual value at the end of its useful life What is the depreciation expense for 2018?

a. $40,000
b. $10,000
c. $30,000
d. $20,000