On January 1, 2014, Lefty, Inc

On January 1, 2014, Lefty, Inc. purchased a machine for $6,000. The estimated life and residual value were five years and $150, respectively. The machine will produce approximately 80,000 units over its life. In 2014 and 2015, the machine produced 10,000 and 15,000 units, respectively. In 2015, Lefty recorded $1,440 of depreciation expense. The depreciation method in use was the

A) activity method
B) sum-of-the-years'-digits method
C) double-declining-balance method
D) straight-line method