On January 1, 2010, Lefler, Inc

On January 1, 2010, Lefler, 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 2010 and 2011, the machine produced 10, 000 and 15, 000 units, respectively.In 2011, Lefler 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