The Doodad Company purchases a machine for $440,000. The machine has an estimated residual value of $40,000. The company expects the machine to produce eight million units. The machine is used to make 700,000 units during the current period.

If the units-of-production method is used, the depreciation expense for this period is:

a. $38,500.
b. $700,000.
c. $660,000.
d.$35,000.